![\"\"](\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/09\/20260902013254-6a977cc65556c.png\")
<\/p>\n\u6211\u76ee\u524d\u5bf9\u201c\u53cc\u6307\u9488\u201d\u7684\u7406\u89e3\u662f：\u5728\u904d\u5386\u6570\u7ec4\u3001\u6570\u5b57\u72b6\u6001\u6216\u5019\u9009\u533a\u95f4\u65f6，\u540c\u65f6\u7ef4\u62a4\u4e24\u4e2a\u4f1a\u79fb\u52a8\u7684\u4f4d\u7f6e，\u5e76\u8ba9\u5b83\u4eec\u627f\u62c5\u4e0d\u540c\u7684\u804c\u8d23\u3002\u8fd9\u6837\u505a\u7684\u4ef7\u503c\u4e0d\u53ea\u662f\u4ee3\u7801\u91cc\u51fa\u73b0\u4e86\u4e24\u4e2a\u53d8\u91cf，\u800c\u662f\u6bcf\u6b21\u79fb\u52a8\u90fd\u80fd\u6839\u636e\u9898\u76ee\u7684\u89c4\u5f8b\u6392\u9664\u4e00\u6279\u4e0d\u53ef\u80fd\u7684\u60c5\u51b5，\u4ece\u800c\u51cf\u5c11\u91cd\u590d\u679a\u4e3e\u3002<\/p>\n
\u5f88\u591a\u76f4\u63a5\u679a\u4e3e\u7684\u5199\u6cd5\u4f1a\u4ea7\u751f\u4e24\u5c42\u3001\u4e09\u5c42\u751a\u81f3\u56db\u5c42\u5faa\u73af\u3002\u53cc\u6307\u9488\u5e76\u4e0d\u80fd\u628a\u6240\u6709\u95ee\u9898\u90fd\u53d8\u6210\u7ebf\u6027\u590d\u6742\u5ea6，\u4f46\u5728\u6570\u636e\u6709\u5e8f\u3001\u7ed3\u679c\u5177\u6709\u5355\u8c03\u6027，\u6216\u8005\u6570\u7ec4\u9700\u8981\u539f\u5730\u8bfb\u5199\u65f6，\u5b83\u7ecf\u5e38\u53ef\u4ee5\u628a\u4e00\u90e8\u5206\u91cd\u590d\u641c\u7d22\u538b\u7f29\u6389\u3002<\/p>\n
\u672c\u6587\u6574\u7406\u516b\u9053\u9898：283 \u79fb\u52a8\u96f6\u30011089 \u590d\u5199\u96f6\u3001202 \u5feb\u4e50\u6570\u300111 \u76db\u6700\u591a\u6c34\u7684\u5bb9\u5668\u3001611 \u6709\u6548\u4e09\u89d2\u5f62\u7684\u4e2a\u6570\u3001LCR 179 \u4e24\u6570\u4e4b\u548c\u300115 \u4e09\u6570\u4e4b\u548c\u300118 \u56db\u6570\u4e4b\u548c\u3002\u8303\u56f4\u4e3b\u8981\u96c6\u4e2d\u5728\u56db\u79cd\u6a21\u5f0f：<\/p>\n
\u8fd9\u91cc\u7684\u201c\u539f\u5730\u201d\u662f\u6307\u76f4\u63a5\u4fee\u6539\u8f93\u5165\u6570\u7ec4，\u4e0d\u989d\u5916\u521b\u5efa\u4e00\u4e2a\u540c\u7b49\u89c4\u6a21\u7684\u65b0\u6570\u7ec4；\u201c\u53bb\u91cd\u201d\u662f\u6307\u907f\u514d\u540c\u4e00\u4e2a\u7b54\u6848\u56e0\u4e3a\u6570\u7ec4\u4e2d\u51fa\u73b0\u91cd\u590d\u6570\u5b57\u800c\u88ab\u52a0\u5165\u591a\u6b21\u3002\u4e0b\u9762\u6309\u9898\u53f7\u9010\u9898\u6574\u7406\u6211\u5bf9\u6307\u9488\u542b\u4e49\u3001\u79fb\u52a8\u7406\u7531\u548c\u4ee3\u7801\u7ec6\u8282\u7684\u7406\u89e3\u3002<\/p>\n
\u9898\u76ee\u63cf\u8ff0<\/p>\n
\u7ed9\u5b9a\u4e00\u4e2a\u6570\u7ec4 nums，\u5c06\u6570\u7ec4\u4e2d\u7684\u6240\u6709 0 \u79fb\u52a8\u5230\u6570\u7ec4\u672b\u5c3e，\u540c\u65f6\u4fdd\u6301\u975e\u96f6\u5143\u7d20\u539f\u6765\u7684\u76f8\u5bf9\u987a\u5e8f\u3002\u8981\u6c42\u76f4\u63a5\u4fee\u6539\u8f93\u5165\u6570\u7ec4，\u4e5f\u5c31\u662f\u539f\u5730\u5b8c\u6210，\u4e0d\u80fd\u8fd4\u56de\u4e00\u4e2a\u65b0\u7684\u5b8c\u6574\u6570\u7ec4\u3002<\/p>\n
\u4f8b\u5982，[0, 1, 0, 3, 12] \u5904\u7406\u540e\u53d8\u4e3a [1, 3, 12, 0, 0]\u3002<\/p>\n
\u9898\u76ee\u94fe\u63a5<\/p>\n
LeetCode 283. \u79fb\u52a8\u96f6<\/p>\n
\u7b97\u6cd5\u601d\u8def<\/p>\n
\u8fd9\u9053\u9898\u9002\u5408\u540c\u5411\u5feb\u6162\u6307\u9488\u3002\u6211\u7684\u5224\u65ad\u4f9d\u636e\u662f：\u9898\u76ee\u8981\u6c42\u628a\u201c\u6ee1\u8db3\u6761\u4ef6\u7684\u5143\u7d20\u201d\u96c6\u4e2d\u5230\u6570\u7ec4\u524d\u9762，\u540c\u65f6\u4fdd\u7559\u5b83\u4eec\u539f\u6765\u7684\u987a\u5e8f，\u5e76\u4e14\u8981\u6c42\u539f\u5730\u4fee\u6539\u3002<\/p>\n
\u53ef\u4ee5\u628a\u4efb\u52a1\u62c6\u6210\u4e24\u6b65：\u5148\u628a\u6240\u6709\u975e\u96f6\u6570\u6309\u539f\u987a\u5e8f\u5199\u5230\u6570\u7ec4\u524d\u9762，\u518d\u628a\u5269\u4f59\u4f4d\u7f6e\u8865\u6210\u96f6\u3002<\/p>\n
\u8fd9\u91cc\u4e0d\u9700\u8981\u5728\u6bcf\u9047\u5230\u4e00\u4e2a\u96f6\u65f6\u642c\u52a8\u540e\u9762\u7684\u6574\u6bb5\u5143\u7d20\u3002\u90a3\u79cd\u505a\u6cd5\u867d\u7136\u5bb9\u6613\u60f3\u5230，\u4f46\u591a\u4e2a\u96f6\u4f1a\u53cd\u590d\u642c\u52a8\u540c\u4e00\u6279\u6570\u636e，\u6700\u574f\u60c5\u51b5\u4e0b\u4f1a\u8fbe\u5230 O(n\u00b2)\u3002\u5feb\u6162\u6307\u9488\u628a\u201c\u5bfb\u627e\u975e\u96f6\u5143\u7d20\u201d\u548c\u201c\u653e\u7f6e\u975e\u96f6\u5143\u7d20\u201d\u5206\u5f00，\u6bcf\u4e2a\u5143\u7d20\u53ea\u88ab\u626b\u63cf\u548c\u5904\u7406\u6709\u9650\u6b21\u3002<\/p>\n
slow \u4e0d\u4f1a\u8d85\u8fc7 fast，\u56e0\u6b64\u5199\u5165\u52a8\u4f5c\u4e0d\u4f1a\u8986\u76d6\u53f3\u4fa7\u8fd8\u6ca1\u6709\u8bfb\u5230\u7684\u5143\u7d20\u3002\u5f53 slow \u548c fast \u76f8\u7b49\u65f6，\u5f53\u524d\u975e\u96f6\u5143\u7d20\u76f8\u5f53\u4e8e\u5199\u56de\u539f\u5904，\u4e5f\u4e0d\u4f1a\u6709\u95ee\u9898\u3002<\/p>\n
Java\u4ee3\u7801<\/p>\n
class Solution {
\n public void moveZeroes(int[] nums) {
\n int slow = 0;<\/p>\n
for (int fast = 0; fast < nums.length; fast++) {
\n if (nums[fast] != 0) {
\n nums[slow] = nums[fast];
\n slow++;
\n }
\n }<\/p>\n
while (slow < nums.length) {
\n nums[slow] = 0;
\n slow++;
\n }
\n }
\n}<\/p>\n
\u4ee3\u7801\u8bf4\u660e<\/p>\n
slow \u521d\u59cb\u4e3a 0，\u8868\u793a\u7b2c\u4e00\u4e2a\u975e\u96f6\u6570\u5e94\u5f53\u5199\u5165\u7684\u4f4d\u7f6e\u3002fast \u626b\u63cf\u5230\u975e\u96f6\u503c\u65f6，nums[slow] = nums[fast] \u5c06\u5b83\u5199\u5165\u5f53\u524d\u5e94\u8be5\u4fdd\u7559\u7684\u533a\u57df，\u7136\u540e slow++ \u4e3a\u4e0b\u4e00\u4e2a\u975e\u96f6\u503c\u9884\u7559\u4f4d\u7f6e\u3002<\/p>\n
\u626b\u63cf\u7ed3\u675f\u65f6，\u533a\u95f4 [0, slow) \u4e2d\u5df2\u7ecf\u6309\u539f\u6709\u987a\u5e8f\u653e\u5165\u6240\u6709\u975e\u96f6\u6570\u3002\u8fd9\u91cc\u7684\u53f3\u8fb9\u754c slow \u4e0d\u5305\u542b\u5728\u5df2\u5b8c\u6210\u533a\u57df\u4e2d，\u6240\u4ee5\u4ece slow \u5f00\u59cb\u8865\u96f6\u5373\u53ef\u3002<\/p>\n
\u4f8b\u5982\u8f93\u5165 [0, 1, 0, 3, 12]，\u975e\u96f6\u6570\u4f9d\u6b21\u662f 1\u30013\u300112，\u5b83\u4eec\u4f1a\u88ab\u5199\u5230\u4e0b\u6807 0\u30011\u30012，\u6700\u540e\u4e0b\u6807 3\u30014 \u5199\u6210\u96f6\u3002<\/p>\n
\u590d\u6742\u5ea6\u4e0e\u6613\u9519\u70b9<\/p>\n
\u6613\u9519\u70b9\u4e3b\u8981\u6709\u4ee5\u4e0b\u51e0\u4e2a：<\/p>\n
\u8fd9\u9053\u9898\u8ba9\u6211\u5148\u8ba4\u8bc6\u5230\u4e00\u79cd\u5f88\u5e38\u89c1\u7684\u53cc\u6307\u9488\u804c\u8d23\u5206\u5de5：fast \u8d1f\u8d23\u627e，slow \u8d1f\u8d23\u653e\u3002\u540e\u9762\u7684\u540c\u5411\u6570\u7ec4\u9898\u4e5f\u53ef\u4ee5\u5148\u4ece\u8fd9\u4e2a\u89d2\u5ea6\u5224\u65ad\u3002<\/p>\n
\u9898\u76ee\u63cf\u8ff0<\/p>\n
\u7ed9\u5b9a\u4e00\u4e2a\u56fa\u5b9a\u957f\u5ea6\u7684\u6570\u7ec4 arr，\u6bcf\u9047\u5230\u4e00\u4e2a\u96f6，\u5c31\u5728\u5b83\u540e\u9762\u590d\u5236\u4e00\u4e2a\u96f6，\u5e76\u5c06\u53f3\u4fa7\u5143\u7d20\u4f9d\u6b21\u5411\u53f3\u79fb\u52a8\u3002\u8d85\u51fa\u6570\u7ec4\u957f\u5ea6\u7684\u5143\u7d20\u4f1a\u88ab\u4e22\u5f03\u3002\u8981\u6c42\u539f\u5730\u4fee\u6539\u6570\u7ec4，\u6570\u7ec4\u957f\u5ea6\u4fdd\u6301\u4e0d\u53d8\u3002<\/p>\n
\u4f8b\u5982，[1, 0, 2, 3, 0, 4, 5, 0] \u5904\u7406\u540e\u4e3a [1, 0, 0, 2, 3, 0, 0, 4]\u3002<\/p>\n
\u9898\u76ee\u94fe\u63a5<\/p>\n
LeetCode 1089. \u590d\u5199\u96f6<\/p>\n
\u7b97\u6cd5\u601d\u8def<\/p>\n
\u8fd9\u9053\u9898\u548c\u79fb\u52a8\u96f6\u7684\u533a\u522b\u5728\u4e8e：\u5143\u7d20\u4e0d\u662f\u88ab\u7b5b\u9009\u540e\u5360\u4e00\u4e2a\u4f4d\u7f6e，\u800c\u662f\u96f6\u4f1a\u989d\u5916\u5360\u7528\u4e00\u4e2a\u4f4d\u7f6e\u3002\u6570\u7ec4\u4ecd\u7136\u662f\u56fa\u5b9a\u957f\u5ea6，\u56e0\u6b64\u4ece\u524d\u5411\u540e\u76f4\u63a5\u5199\u4f1a\u8986\u76d6\u540e\u9762\u8fd8\u6ca1\u6709\u8bfb\u53d6\u7684\u5143\u7d20\u3002<\/p>\n
\u6211\u628a\u5b83\u7406\u89e3\u6210\u4e00\u4e2a\u201c\u865a\u62df\u6269\u5bb9\u6570\u7ec4\u201d：\u666e\u901a\u6570\u5b57\u5728\u865a\u62df\u6570\u7ec4\u4e2d\u5360\u4e00\u4e2a\u4f4d\u7f6e，\u96f6\u5360\u4e24\u4e2a\u4f4d\u7f6e\u3002\u5b9e\u9645\u6570\u7ec4\u5e76\u6ca1\u6709\u771f\u7684\u6269\u5bb9，\u53ea\u662f\u5148\u6309\u7167\u8fd9\u4e2a\u89c4\u5219\u8ba1\u7b97\u6bcf\u4e2a\u539f\u5143\u7d20\u5728\u865a\u62df\u6570\u7ec4\u4e2d\u7684\u4f4d\u7f6e\u3002<\/p>\n
\u5177\u4f53\u505a\u6cd5\u5982\u4e0b：<\/p>\n
\u4ece\u540e\u5411\u524d\u5199\u7684\u597d\u5904\u662f，\u5199\u5165\u4f4d\u7f6e\u4f4d\u4e8e\u5f53\u524d\u8bfb\u53d6\u4f4d\u7f6e\u7684\u53f3\u4fa7，\u6216\u8005\u4e0e\u5f53\u524d\u8bfb\u53d6\u4f4d\u7f6e\u91cd\u5408，\u4e0d\u4f1a\u7834\u574f\u5de6\u4fa7\u5c1a\u672a\u8bfb\u53d6\u7684\u5185\u5bb9\u3002\u82e5\u865a\u62df\u4f4d\u7f6e\u5df2\u7ecf\u8d85\u51fa\u771f\u5b9e\u6570\u7ec4\u8fb9\u754c，\u53ea\u8ba1\u7b97\u4f4d\u7f6e\u800c\u4e0d\u5b9e\u9645\u8d4b\u503c\u3002<\/p>\n
Java\u4ee3\u7801<\/p>\n
class Solution {
\n public void duplicateZeros(int[] nums) {
\n int zeros = 0;
\n for (int num : nums) {
\n if (num == 0) {
\n zeros++;
\n }
\n }<\/p>\n
int i = nums.length – 1;
\n int j = nums.length + zeros – 1;<\/p>\n
while (i >= 0) {
\n if (j < nums.length) {
\n nums[j] = nums[i];
\n }<\/p>\n
if (nums[i] == 0) {
\n j–;
\n if (j < nums.length) {
\n nums[j] = 0;
\n }
\n }<\/p>\n
i–;
\n j–;
\n }
\n }
\n}<\/p>\n
\u4ee3\u7801\u8bf4\u660e<\/p>\n
zeros \u8868\u793a\u6240\u6709\u96f6\u5728\u865a\u62df\u6570\u7ec4\u4e2d\u591a\u5360\u51fa\u6765\u7684\u683c\u6570，\u56e0\u6b64\u865a\u62df\u6570\u7ec4\u6700\u540e\u4e00\u4e2a\u4e0b\u6807\u662f nums.length + zeros – 1\u3002<\/p>\n
i \u59cb\u7ec8\u6307\u5411\u771f\u5b9e\u6570\u7ec4\u4e2d\u8fd8\u6ca1\u6709\u5904\u7406\u7684\u539f\u5143\u7d20，j \u6307\u5411\u8fd9\u4e2a\u539f\u5143\u7d20\u5728\u865a\u62df\u5e03\u5c40\u4e2d\u5e94\u8be5\u5199\u5165\u7684\u4f4d\u7f6e\u3002\u666e\u901a\u5143\u7d20\u53ea\u5360\u4e00\u683c，\u6240\u4ee5\u5199\u5b8c\u540e j–；\u96f6\u5360\u4e24\u683c，\u6240\u4ee5\u5148\u5199\u4e00\u4efd，\u518d\u989d\u5916 j– \u5199\u7b2c\u4e8c\u4efd\u96f6，\u6700\u540e\u518d\u7edf\u4e00 j– \u8fdb\u5165\u524d\u4e00\u4e2a\u539f\u5143\u7d20\u5bf9\u5e94\u7684\u533a\u57df\u3002<\/p>\n
\u8fb9\u754c\u5224\u65ad\u53ea\u5728\u5199\u5165\u524d\u8fdb\u884c\u3002\u6bd4\u5982\u865a\u62df\u6570\u7ec4\u7684\u672b\u5c3e\u53ef\u80fd\u8d85\u8fc7\u771f\u5b9e\u6570\u7ec4\u672b\u5c3e，\u8fd9\u4e9b\u4f4d\u7f6e\u867d\u7136\u53c2\u4e0e\u4e86\u8ba1\u7b97，\u4f46\u4e0d\u80fd\u8bbf\u95ee nums[j]\u3002\u56e0\u6b64 if (j < nums.length) \u662f\u907f\u514d\u6570\u7ec4\u8d8a\u754c\u7684\u5173\u952e\u3002<\/p>\n
\u590d\u6742\u5ea6\u4e0e\u6613\u9519\u70b9<\/p>\n
\u6613\u9519\u70b9\u5305\u62ec：<\/p>\n
\u548c\u79fb\u52a8\u96f6\u653e\u5728\u4e00\u8d77\u770b，\u4e8c\u8005\u90fd\u5c5e\u4e8e\u539f\u5730\u8bfb\u5199，\u4f46\u65b9\u5411\u76f8\u53cd：\u5982\u679c\u5199\u5165\u4e0d\u4f1a\u589e\u52a0\u5143\u7d20\u6570\u91cf，\u53ef\u4ee5\u4ece\u524d\u5411\u540e\u7528\u5feb\u6162\u6307\u9488；\u5982\u679c\u4e00\u4e2a\u5143\u7d20\u53ef\u80fd\u6269\u5c55\u6210\u591a\u4e2a\u4f4d\u7f6e，\u5e76\u4e14\u524d\u5199\u4f1a\u8986\u76d6\u672a\u8bfb\u6570\u636e，\u5c31\u66f4\u9002\u5408\u4ece\u540e\u5411\u524d\u5904\u7406\u3002<\/p>\n
\u9898\u76ee\u63cf\u8ff0<\/p>\n
\u7ed9\u5b9a\u4e00\u4e2a\u6b63\u6574\u6570 n，\u4e0d\u65ad\u5c06\u5b83\u66ff\u6362\u4e3a\u5404\u4f4d\u6570\u5b57\u7684\u5e73\u65b9\u548c\u3002\u5982\u679c\u6700\u7ec8\u5f97\u5230 1，\u90a3\u4e48\u8fd9\u4e2a\u6570\u5c31\u662f\u5feb\u4e50\u6570；\u5982\u679c\u8ba1\u7b97\u8fc7\u7a0b\u8fdb\u5165\u4e00\u4e2a\u4e0d\u5305\u542b 1 \u7684\u5faa\u73af，\u5219\u5b83\u4e0d\u662f\u5feb\u4e50\u6570\u3002<\/p>\n
\u4f8b\u5982，19 \u2192 82 \u2192 68 \u2192 100 \u2192 1，\u6240\u4ee5 19 \u662f\u5feb\u4e50\u6570\u3002<\/p>\n
\u9898\u76ee\u94fe\u63a5<\/p>\n
LeetCode 202. \u5feb\u4e50\u6570<\/p>\n
\u7b97\u6cd5\u601d\u8def<\/p>\n
\u8fd9\u9053\u9898\u8868\u9762\u4e0a\u6ca1\u6709\u6570\u7ec4\u4e0b\u6807，\u4f46\u4ecd\u7136\u53ef\u4ee5\u4f7f\u7528\u5feb\u6162\u6307\u9488\u3002\u6bcf\u4e2a\u6570\u5b57\u90fd\u53ef\u4ee5\u770b\u6210\u4e00\u4e2a\u72b6\u6001，\u8ba1\u7b97\u201c\u5404\u4f4d\u6570\u5b57\u5e73\u65b9\u548c\u201d\u5c31\u662f\u4ece\u5f53\u524d\u72b6\u6001\u8d70\u5411\u4e0b\u4e00\u4e2a\u72b6\u6001\u3002<\/p>\n
\u5982\u679c\u4e00\u4e2a\u72b6\u6001\u5e8f\u5217\u6700\u7ec8\u5230\u8fbe 1，\u7531\u4e8e 1 \u7684\u4e0b\u4e00\u4e2a\u72b6\u6001\u4ecd\u7136\u662f 1，\u6240\u4ee5\u5b83\u4f1a\u8fdb\u5165 1 \u8fd9\u4e2a\u957f\u5ea6\u4e3a\u4e00\u7684\u73af\u3002\u5982\u679c\u4e0d\u662f\u5feb\u4e50\u6570，\u5e8f\u5217\u4e5f\u4f1a\u8fdb\u5165\u53e6\u4e00\u4e2a\u73af\u3002\u95ee\u9898\u7684\u5173\u952e\u5c31\u53d8\u6210\u4e86：\u72b6\u6001\u5e8f\u5217\u662f\u5426\u6210\u73af，\u4ee5\u53ca\u76f8\u9047\u65f6\u7684\u72b6\u6001\u662f\u4e0d\u662f 1\u3002<\/p>\n
\u505a\u6cd5\u662f：<\/p>\n
\u8fd9\u91cc\u5c06\u6570\u5b57\u72b6\u6001\u5f53\u6210\u94fe\u8868\u8282\u70b9，getNext \u5c31\u7c7b\u4f3c\u4e8e\u94fe\u8868\u8282\u70b9\u7684 next\u3002\u5feb\u6162\u6307\u9488\u4e0d\u4e00\u5b9a\u53ea\u80fd\u64cd\u4f5c\u6570\u7ec4\u6216\u94fe\u8868，\u53ea\u8981\u5bf9\u8c61\u4e4b\u95f4\u5b58\u5728\u201c\u4e0b\u4e00\u6b65\u201d\u7684\u5173\u7cfb，\u5c31\u53ef\u80fd\u7528\u6765\u5224\u65ad\u73af\u3002<\/p>\n
Java\u4ee3\u7801<\/p>\n
class Solution {
\n public boolean isHappy(int n) {
\n int slow = n;
\n int fast = getNext(n);<\/p>\n
while (slow != fast) {
\n slow = getNext(slow);
\n fast = getNext(getNext(fast));
\n }<\/p>\n
return slow == 1;
\n }<\/p>\n
private int getNext(int n) {
\n int sum = 0;<\/p>\n
while (n > 0) {
\n int digit = n % 10;
\n sum += digit * digit;
\n n \/= 10;
\n }<\/p>\n
return sum;
\n }
\n}<\/p>\n
\u4ee3\u7801\u8bf4\u660e<\/p>\n
getNext(int n) \u8d1f\u8d23\u8ba1\u7b97\u4e0b\u4e00\u4e2a\u72b6\u6001\u3002n % 10 \u53d6\u51fa\u5f53\u524d\u4e2a\u4f4d\u6570\u5b57，n \/= 10 \u53bb\u6389\u4e2a\u4f4d，\u5faa\u73af\u7ed3\u675f\u65f6\u5c31\u5f97\u5230\u4e86\u6240\u6709\u4f4d\u6570\u5b57\u5e73\u65b9\u548c\u3002<\/p>\n
\u8fd9\u91cc\u5c06 slow \u521d\u59cb\u5316\u4e3a n，\u5c06 fast \u521d\u59cb\u5316\u4e3a getNext(n)，\u76f8\u5f53\u4e8e\u8ba9\u5feb\u6307\u9488\u5148\u8d70\u4e00\u6b65\u3002\u8fd9\u6837\u53ef\u4ee5\u76f4\u63a5\u4f7f\u7528\u666e\u901a\u7684 while (slow != fast)\u3002\u5982\u679c\u4e24\u4e2a\u6307\u9488\u90fd\u521d\u59cb\u5316\u4e3a n，\u5219\u9700\u8981\u91c7\u7528 do…while \u6216\u5176\u4ed6\u65b9\u5f0f\u4fdd\u8bc1\u81f3\u5c11\u5148\u6267\u884c\u4e00\u6b21\u79fb\u52a8\u3002<\/p>\n
\u975e\u5feb\u4e50\u6570 2 \u7684\u53d8\u5316\u8fc7\u7a0b\u4f1a\u51fa\u73b0：2 \u2192 4 \u2192 16 \u2192 37 \u2192 58 \u2192 89 \u2192 145 \u2192 42 \u2192 20 \u2192 4\u3002\u518d\u6b21\u9047\u5230 4 \u5c31\u8bf4\u660e\u8fdb\u5165\u4e86\u5faa\u73af，\u5feb\u6162\u6307\u9488\u4f1a\u5728\u8fd9\u4e2a\u73af\u4e2d\u76f8\u9047，\u800c\u76f8\u9047\u503c\u4e0d\u662f 1\u3002<\/p>\n
\u590d\u6742\u5ea6\u4e0e\u6613\u9519\u70b9<\/p>\n
\u6613\u9519\u70b9\u5305\u62ec：<\/p>\n
\u9898\u76ee\u63cf\u8ff0<\/p>\n
\u7ed9\u5b9a\u4e00\u4e2a\u6574\u6570\u6570\u7ec4 height，\u5176\u4e2d height[i] \u8868\u793a\u4f4d\u4e8e\u4e0b\u6807 i \u7684\u7ad6\u7ebf\u9ad8\u5ea6\u3002\u9009\u62e9\u4e24\u6761\u4e0d\u540c\u7684\u7ad6\u7ebf，\u4e0e\u6a2a\u8f74\u5171\u540c\u6784\u6210\u4e00\u4e2a\u5bb9\u5668，\u6c42\u8fd9\u4e2a\u5bb9\u5668\u80fd\u591f\u76db\u653e\u7684\u6700\u5927\u6c34\u91cf\u3002<\/p>\n
\u5bb9\u5668\u9762\u79ef\u7531\u4e24\u90e8\u5206\u51b3\u5b9a：\u4e24\u6761\u7ebf\u4e4b\u95f4\u7684\u5bbd\u5ea6，\u4ee5\u53ca\u4e24\u6761\u7ebf\u4e2d\u8f83\u77ed\u7684\u9ad8\u5ea6\u3002\u9762\u79ef\u516c\u5f0f\u662f min(height[left], height[right]) * (right – left)\u3002<\/p>\n
\u9898\u76ee\u94fe\u63a5<\/p>\n
LeetCode 11. \u76db\u6700\u591a\u6c34\u7684\u5bb9\u5668<\/p>\n
\u7b97\u6cd5\u601d\u8def<\/p>\n
\u8fd9\u662f\u76f8\u5411\u53cc\u6307\u9488\u7684\u5178\u578b\u9898\u3002\u5f00\u59cb\u65f6\u8ba9 left \u4f4d\u4e8e\u6700\u5de6\u7aef\u3001right \u4f4d\u4e8e\u6700\u53f3\u7aef，\u6b64\u65f6\u5bbd\u5ea6\u6700\u5927\u3002\u6bcf\u4e00\u8f6e\u5148\u8ba1\u7b97\u5f53\u524d\u5bb9\u5668\u9762\u79ef，\u518d\u51b3\u5b9a\u79fb\u52a8\u54ea\u4e00\u4fa7\u3002<\/p>\n
\u6c34\u4f4d\u53d7\u5230\u77ed\u677f\u9650\u5236，\u6240\u4ee5\u5982\u679c\u5de6\u8fb9\u9ad8\u5ea6\u8f83\u5c0f，\u7ee7\u7eed\u4fdd\u7559\u5de6\u8fb9\u800c\u53ea\u8ba9\u53f3\u8fb9\u5411\u5185\u79fb\u52a8\u65f6：<\/p>\n
\u56e0\u6b64，\u5de6\u8fb9\u8f83\u77ed\u65f6，\u5f53\u524d\u5de6\u8fb9\u754c\u5bf9\u5e94\u7684\u5176\u4ed6\u66f4\u7a84\u7ec4\u5408\u90fd\u53ef\u4ee5\u6392\u9664，\u53ea\u6709\u6362\u6389\u5de6\u8fb9\u3001\u5bfb\u627e\u66f4\u9ad8\u7684\u5de6\u8fb9\u754c\u624d\u6709\u53ef\u80fd\u4ea7\u751f\u66f4\u5927\u7684\u9762\u79ef\u3002\u53f3\u8fb9\u8f83\u77ed\u65f6\u540c\u7406\u3002<\/p>\n
\u8fd9\u5c31\u662f\u201c\u79fb\u52a8\u77ed\u8fb9\u201d\u7684\u4f9d\u636e，\u4e0d\u662f\u4e00\u4e2a\u8131\u79bb\u9898\u76ee\u6761\u4ef6\u7684\u56fa\u5b9a\u53e3\u8bc0\u3002\u5b83\u4f9d\u8d56\u4e8e\u9762\u79ef\u4e2d\u7684\u77ed\u677f\u9650\u5236\u548c\u5bbd\u5ea6\u5355\u8c03\u53d8\u5c0f\u8fd9\u4e24\u4e2a\u4e8b\u5b9e\u3002\u5f53\u4e24\u8fb9\u4e00\u6837\u9ad8\u65f6，\u79fb\u52a8\u4efb\u610f\u4e00\u8fb9\u90fd\u53ef\u4ee5，\u4ee3\u7801\u4e2d\u9009\u62e9\u79fb\u52a8\u5de6\u8fb9\u3002<\/p>\n
Java\u4ee3\u7801<\/p>\n
class Solution {
\n public int maxArea(int[] height) {
\n int left = 0;
\n int right = height.length – 1;
\n int ret = 0;<\/p>\n
while (left < right) {
\n int width = right – left;
\n int minHeight = Math.min(height[left], height[right]);
\n int area = width * minHeight;
\n ret = Math.max(ret, area);<\/p>\n
if (height[left] <= height[right]) {
\n left++;
\n } else {
\n right–;
\n }
\n }<\/p>\n
return ret;
\n }
\n}<\/p>\n
\u4ee3\u7801\u8bf4\u660e<\/p>\n
left \u548c right \u8868\u793a\u5f53\u524d\u8fd8\u6ca1\u6709\u6392\u9664\u7684\u4e24\u6761\u8fb9\u3002\u5bbd\u5ea6\u662f\u4e0b\u6807\u5dee right – left，\u4e0d\u662f\u5143\u7d20\u4e2a\u6570，\u6240\u4ee5\u4e0d\u9700\u8981\u52a0\u4e00\u3002<\/p>\n
\u6bcf\u8f6e\u5148\u901a\u8fc7 Math.min \u6c42\u51fa\u77ed\u677f\u9ad8\u5ea6，\u518d\u8ba1\u7b97\u9762\u79ef\u5e76\u66f4\u65b0 ret\u3002\u66f4\u65b0\u5b8c\u5f53\u524d\u7ec4\u5408\u540e，\u6839\u636e\u4e24\u8fb9\u9ad8\u5ea6\u51b3\u5b9a\u79fb\u52a8\u77ed\u8fb9\u3002\u5faa\u73af\u6761\u4ef6\u662f left < right，\u56e0\u4e3a\u540c\u4e00\u4e2a\u4e0b\u6807\u4e0d\u80fd\u5f62\u6210\u6709\u5bbd\u5ea6\u7684\u5bb9\u5668\u3002<\/p>\n
\u4f8b\u5982\u6570\u7ec4 [1,8,6,2,5,4,8,3,7]，\u6700\u521d\u4e24\u7aef\u5f62\u6210\u9762\u79ef 8\u3002\u5de6\u8fb9\u9ad8\u5ea6 1 \u662f\u77ed\u677f，\u79fb\u52a8\u5de6\u6307\u9488\u540e，\u8fb9\u754c\u6765\u5230\u9ad8\u5ea6 8，\u6b64\u65f6\u4e0e\u53f3\u7aef\u9ad8\u5ea6 7 \u5f62\u6210\u9762\u79ef 7 * 7 = 49，\u540e\u7eed\u641c\u7d22\u4e0d\u4f1a\u5f97\u5230\u66f4\u5927\u7ed3\u679c\u3002<\/p>\n
\u590d\u6742\u5ea6\u4e0e\u6613\u9519\u70b9<\/p>\n
\u6613\u9519\u70b9\u5305\u62ec：<\/p>\n
\u9898\u76ee\u63cf\u8ff0<\/p>\n
\u7ed9\u5b9a\u4e00\u4e2a\u5305\u542b\u975e\u8d1f\u6574\u6570\u7684\u6570\u7ec4 nums，\u7edf\u8ba1\u4ece\u6570\u7ec4\u4e2d\u9009\u62e9\u4e09\u4e2a\u4e0b\u6807\u540e，\u80fd\u591f\u7ec4\u6210\u4e09\u89d2\u5f62\u7684\u7ec4\u5408\u6570\u91cf\u3002\u76f8\u540c\u6570\u503c\u5982\u679c\u6765\u81ea\u4e0d\u540c\u4e0b\u6807，\u4ecd\u7136\u5c5e\u4e8e\u4e0d\u540c\u7684\u4e0b\u6807\u7ec4\u5408，\u9700\u8981\u5206\u522b\u8ba1\u6570\u3002<\/p>\n
\u4e09\u89d2\u5f62\u6210\u7acb\u7684\u6761\u4ef6\u662f：\u4e24\u6761\u8f83\u77ed\u8fb9\u4e4b\u548c\u4e25\u683c\u5927\u4e8e\u6700\u957f\u8fb9\u3002<\/p>\n
\u9898\u76ee\u94fe\u63a5<\/p>\n
LeetCode 611. \u6709\u6548\u4e09\u89d2\u5f62\u7684\u4e2a\u6570<\/p>\n
\u7b97\u6cd5\u601d\u8def<\/p>\n
\u76f4\u63a5\u4f7f\u7528\u4e09\u5c42\u5faa\u73af\u4f1a\u5f97\u5230 O(n\u00b3)\u3002\u6392\u5e8f\u4ee5\u540e，\u53ef\u4ee5\u56fa\u5b9a\u6700\u957f\u8fb9，\u518d\u7528\u5de6\u53f3\u6307\u9488\u6279\u91cf\u7edf\u8ba1\u6ee1\u8db3\u6761\u4ef6\u7684\u7ec4\u5408\u3002<\/p>\n
\u5148\u5bf9\u6570\u7ec4\u5347\u5e8f\u6392\u5e8f\u3002\u4ee4 i \u4ece\u6570\u7ec4\u672b\u5c3e\u5411\u524d\u79fb\u52a8，\u628a nums[i] \u4f5c\u4e3a\u5f53\u524d\u56fa\u5b9a\u7684\u6700\u957f\u8fb9\u3002\u5269\u4e0b\u7684\u4e24\u6761\u8fb9\u5728 [0, i – 1] \u4e2d\u9009\u62e9，\u8bbe\u7f6e：<\/p>\n
\u5224\u65ad nums[left] + nums[right] > nums[i]：<\/p>\n
\u8fd9\u91cc\u7684\u6279\u91cf\u8ba1\u6570\u662f\u672c\u9898\u6700\u91cd\u8981\u7684\u5730\u65b9\u3002\u6392\u5e8f\u5e26\u6765\u7684\u5355\u8c03\u6027\u8ba9\u4e00\u6b21\u5224\u65ad\u53ef\u4ee5\u8986\u76d6\u4e00\u6574\u6bb5\u5019\u9009，\u800c\u4e0d\u662f\u9010\u4e2a\u68c0\u67e5\u3002<\/p>\n
Java\u4ee3\u7801<\/p>\n
import java.util.Arrays;<\/p>\n
class Solution {
\n public int triangleNumber(int[] nums) {
\n Arrays.sort(nums);
\n int ret = 0;<\/p>\n
for (int i = nums.length – 1; i >= 2; i–) {
\n int left = 0;
\n int right = i – 1;<\/p>\n
while (left < right) {
\n if (nums[left] + nums[right] > nums[i]) {
\n ret += right – left;
\n right–;
\n } else {
\n left++;
\n }
\n }
\n }<\/p>\n
return ret;
\n }
\n}<\/p>\n
\u4ee3\u7801\u8bf4\u660e<\/p>\n
\u6392\u5e8f\u540e\u56fa\u5b9a\u7684 nums[i] \u662f\u6700\u957f\u8fb9，\u6240\u4ee5\u53ea\u9700\u8981\u5224\u65ad nums[left] + nums[right] > nums[i]\u3002\u53e6\u5916\u4e24\u7ec4\u8fb9\u4e4b\u548c\u4e00\u5b9a\u4e0d\u4f1a\u66f4\u5c0f，\u56e0\u4e3a nums[i] \u5df2\u7ecf\u662f\u4e09\u8005\u4e2d\u7684\u6700\u5927\u503c\u3002<\/p>\n
\u6761\u4ef6\u6210\u7acb\u65f6，\u4e3a\u4ec0\u4e48\u589e\u52a0 right – left \u800c\u4e0d\u662f right – left + 1？\u5f53\u524d right \u5df2\u7ecf\u88ab\u4f5c\u4e3a\u7b2c\u4e8c\u6761\u8fb9\u4f7f\u7528，\u5de6\u8fb9\u53ea\u80fd\u4ece left \u5230 right – 1 \u9009\u62e9，\u5171\u6709 right – left \u4e2a\u4e0b\u6807\u3002\u4e4b\u540e right–，\u7ee7\u7eed\u5904\u7406\u4e0b\u4e00\u6761\u53ef\u80fd\u7684\u7b2c\u4e8c\u957f\u8fb9\u3002<\/p>\n
\u6761\u4ef6\u4e0d\u6210\u7acb\u65f6，\u5f53\u524d left \u548c\u6700\u5927\u7684 right \u90fd\u65e0\u6cd5\u7ec4\u6210\u4e09\u89d2\u5f62，\u56e0\u6b64\u4fdd\u7559\u8fd9\u4e2a left \u6ca1\u6709\u5fc5\u8981，\u76f4\u63a5 left++\u3002<\/p>\n
\u4f8b\u5982\u6392\u5e8f\u540e\u7684 [2, 2, 3, 4]：\u56fa\u5b9a\u6700\u957f\u8fb9 4 \u65f6，3 \u4e0e\u4e24\u4e2a 2 \u90fd\u80fd\u7ec4\u6210\u4e09\u89d2\u5f62，\u4e00\u6b21\u8ba1\u5165\u4e24\u4e2a\u7ec4\u5408；\u56fa\u5b9a\u6700\u957f\u8fb9 3 \u65f6，\u4e24\u4e2a 2 \u53c8\u7ec4\u6210\u4e00\u4e2a\u7ec4\u5408，\u603b\u6570\u4e3a 3\u3002\u8fd9\u91cc\u76f8\u540c\u7684\u8fb9\u957f\u6765\u81ea\u4e0d\u540c\u4e0b\u6807，\u56e0\u6b64\u4e0d\u80fd\u50cf\u4e09\u6570\u4e4b\u548c\u90a3\u6837\u6309\u6570\u503c\u53bb\u91cd\u3002<\/p>\n
\u590d\u6742\u5ea6\u4e0e\u6613\u9519\u70b9<\/p>\n
\u6613\u9519\u70b9\u5305\u62ec：<\/p>\n
\u9898\u76ee\u63cf\u8ff0<\/p>\n
\u7ed9\u5b9a\u4e00\u4e2a\u5df2\u7ecf\u6309\u975e\u9012\u51cf\u987a\u5e8f\u6392\u5217\u7684\u6570\u7ec4 price \u548c\u76ee\u6807\u503c target，\u627e\u51fa\u4e24\u4e2a\u6570，\u4f7f\u5b83\u4eec\u7684\u548c\u7b49\u4e8e target，\u5e76\u8fd4\u56de\u8fd9\u4e24\u4e2a\u6570\u3002\u9898\u76ee\u901a\u5e38\u4fdd\u8bc1\u5b58\u5728\u6ee1\u8db3\u6761\u4ef6\u7684\u7b54\u6848，\u8fd4\u56de\u7684\u662f\u6570\u503c\u800c\u4e0d\u662f\u4e0b\u6807\u3002<\/p>\n
\u9898\u76ee\u94fe\u63a5<\/p>\n
LCR 179. \u67e5\u627e\u603b\u4ef7\u683c\u4e3a\u76ee\u6807\u503c\u7684\u4e24\u4e2a\u5546\u54c1<\/p>\n
\u7b97\u6cd5\u601d\u8def<\/p>\n
\u8fd9\u662f\u6709\u5e8f\u6570\u7ec4\u4e2d\u7684\u6807\u51c6\u76f8\u5411\u53cc\u6307\u9488\u3002left \u4ece\u6700\u5c0f\u503c\u5f00\u59cb，right \u4ece\u6700\u5927\u503c\u5f00\u59cb\u3002\u6bcf\u8f6e\u8ba1\u7b97\u4e24\u7aef\u4e4b\u548c：<\/p>\n
\u79fb\u52a8\u7406\u7531\u4f9d\u8d56\u4e8e\u6570\u7ec4\u6709\u5e8f\u3002\u5982\u679c\u5f53\u524d\u548c\u592a\u5c0f，\u79fb\u52a8 right \u53ea\u4f1a\u8ba9\u53f3\u4fa7\u6570\u53d8\u5c0f，\u7ed3\u679c\u4e0d\u53ef\u80fd\u53d8\u5927，\u56e0\u6b64\u5f53\u524d left \u4e0e\u8fd9\u4e2a right \u7684\u7ec4\u5408\u4ee5\u53ca\u66f4\u5c0f\u7684\u53f3\u4fa7\u7ec4\u5408\u90fd\u53ef\u4ee5\u6392\u9664；\u540c\u7406，\u548c\u592a\u5927\u65f6\u5e94\u6392\u9664\u5f53\u524d right\u3002<\/p>\n
\u5982\u679c\u6570\u7ec4\u65e0\u5e8f，\u5c31\u4e0d\u80fd\u76f4\u63a5\u5957\u7528\u8fd9\u5957\u65b9\u5411\u5224\u65ad\u3002\u65e0\u5e8f\u6570\u7ec4\u901a\u5e38\u9700\u8981\u54c8\u5e0c\u8868，\u6216\u8005\u5148\u6392\u5e8f\u5e76\u540c\u65f6\u4fdd\u7559\u539f\u4e0b\u6807；\u672c\u9898\u5df2\u7ecf\u6709\u5e8f，\u6240\u4ee5\u53cc\u6307\u9488\u53ef\u4ee5\u7528\u5e38\u6570\u7ea7\u989d\u5916\u7a7a\u95f4\u5b8c\u6210\u3002<\/p>\n
Java\u4ee3\u7801<\/p>\n
class Solution {
\n public int[] twoSum(int[] price, int target) {
\n int left = 0;
\n int right = price.length – 1;<\/p>\n
while (left < right) {
\n int sum = price[left] + price[right];<\/p>\n
if (sum == target) {
\n return new int[] {price[left], price[right]};
\n } else if (sum < target) {
\n left++;
\n } else {
\n right–;
\n }
\n }<\/p>\n
return new int[0];
\n }
\n}<\/p>\n
\u4ee3\u7801\u8bf4\u660e<\/p>\n
left \u548c right \u59cb\u7ec8\u6307\u5411\u4e24\u4e2a\u4e0d\u540c\u4f4d\u7f6e，\u6240\u4ee5\u5faa\u73af\u6761\u4ef6\u4e3a left < right\u3002\u5f53 sum == target \u65f6，\u8fd4\u56de\u5305\u542b\u4e24\u4e2a\u4ef7\u683c\u7684\u6570\u7ec4，\u800c\u4e0d\u662f\u8fd4\u56de\u4e24\u4e2a\u4e0b\u6807\u3002<\/p>\n
\u4ee5 price = [2, 7, 11, 15]\u3001target = 9 \u4e3a\u4f8b，\u5f00\u59cb\u65f6 2 + 15 = 17，\u548c\u592a\u5927，\u53f3\u6307\u9488\u5411\u5de6\u79fb\u52a8；\u63a5\u7740 2 + 11 = 13 \u4ecd\u7136\u592a\u5927，\u53f3\u6307\u9488\u7ee7\u7eed\u79fb\u52a8；\u6700\u540e 2 + 7 = 9，\u8fd4\u56de [2, 7]\u3002<\/p>\n
\u65b9\u6cd5\u672b\u5c3e\u7684 return new int[0] \u662f\u4e3a\u4e86\u8986\u76d6\u201c\u6ca1\u6709\u627e\u5230\u7b54\u6848\u201d\u7684\u4ee3\u7801\u8def\u5f84\u3002\u9898\u76ee\u5982\u679c\u4fdd\u8bc1\u7b54\u6848\u5b58\u5728，\u6b63\u5e38\u6267\u884c\u65f6\u4f1a\u5728\u5faa\u73af\u4e2d\u8fd4\u56de；\u8fd9\u884c\u4e0d\u4f1a\u5f71\u54cd\u6838\u5fc3\u7b97\u6cd5\u3002<\/p>\n
\u590d\u6742\u5ea6\u4e0e\u6613\u9519\u70b9<\/p>\n
\u6613\u9519\u70b9\u5305\u62ec：<\/p>\n
\u8fd9\u9053\u9898\u8ba9\u6211\u66f4\u6e05\u695a\u5730\u770b\u5230：\u76f8\u5411\u53cc\u6307\u9488\u7684\u5173\u952e\u4e0d\u662f\u201c\u5de6\u53f3\u5404\u653e\u4e00\u4e2a\u6307\u9488\u201d，\u800c\u662f\u6570\u7ec4\u6709\u5e8f\u540e，\u5f53\u524d\u548c\u7684\u5927\u5c0f\u80fd\u591f\u51b3\u5b9a\u54ea\u4e00\u4fa7\u4e0d\u518d\u6709\u53ef\u80fd\u3002<\/p>\n
\u9898\u76ee\u63cf\u8ff0<\/p>\n
\u7ed9\u5b9a\u4e00\u4e2a\u6574\u6570\u6570\u7ec4 nums，\u627e\u51fa\u6240\u6709\u548c\u4e3a 0 \u4e14\u4e0d\u91cd\u590d\u7684\u4e09\u5143\u7ec4 [nums[i], nums[left], nums[right]]\u3002\u4e09\u5143\u7ec4\u4e2d\u7684\u4e09\u4e2a\u5143\u7d20\u5fc5\u987b\u6765\u81ea\u4e09\u4e2a\u4e0d\u540c\u4e0b\u6807，\u7b54\u6848\u4e2d\u7684\u7ec4\u5408\u987a\u5e8f\u4e0d\u91cd\u8981\u3002<\/p>\n
\u4f8b\u5982，\u8f93\u5165 [-1, 0, 1, 2, -1, -4]，\u7ed3\u679c\u4e3a [[-1, -1, 2], [-1, 0, 1]]\u3002<\/p>\n
\u9898\u76ee\u94fe\u63a5<\/p>\n
LeetCode 15. \u4e09\u6570\u4e4b\u548c<\/p>\n
\u7b97\u6cd5\u601d\u8def<\/p>\n
\u4e09\u6570\u4e4b\u548c\u5982\u679c\u4f7f\u7528\u4e09\u5c42\u5faa\u73af，\u590d\u6742\u5ea6\u662f O(n\u00b3)\u3002\u6392\u5e8f\u540e\u56fa\u5b9a\u7b2c\u4e00\u4e2a\u6570，\u518d\u5728\u53f3\u4fa7\u533a\u95f4\u7528\u5de6\u53f3\u6307\u9488\u5bfb\u627e\u53e6\u5916\u4e24\u4e2a\u6570，\u53ef\u4ee5\u964d\u5230 O(n\u00b2)\u3002<\/p>\n
\u6b65\u9aa4\u5982\u4e0b：<\/p>\n
\u201c\u53bb\u91cd\u201d\u5728\u8fd9\u91cc\u6307\u7684\u662f\u7b54\u6848\u503c\u4e0d\u80fd\u91cd\u590d，\u5e76\u4e0d\u662f\u8bf4\u6570\u7ec4\u4e2d\u76f8\u540c\u5143\u7d20\u53ea\u80fd\u4f7f\u7528\u4e00\u6b21\u3002\u6bd4\u5982 [-1, -1, 2] \u662f\u5408\u6cd5\u7b54\u6848，\u56e0\u4e3a\u4e24\u4e2a -1 \u6765\u81ea\u4e24\u4e2a\u4e0d\u540c\u4e0b\u6807\u3002\u771f\u6b63\u9700\u8981\u8df3\u8fc7\u7684\u662f：\u5f53\u67d0\u4e00\u5c42\u56fa\u5b9a\u7684\u503c\u4e0e\u4e0a\u4e00\u8f6e\u76f8\u540c，\u7ee7\u7eed\u4f7f\u7528\u5b83\u53ea\u4f1a\u751f\u6210\u5df2\u7ecf\u5904\u7406\u8fc7\u7684\u7b54\u6848\u3002<\/p>\n
\u56fa\u5b9a\u5c42\u53bb\u91cd\u5199\u6210 i > 0 && nums[i] == nums[i – 1]\u3002\u627e\u5230\u4e00\u4e2a\u7b54\u6848\u540e，\u5148\u8ba9 left++ \u548c right– \u79bb\u5f00\u5f53\u524d\u7ec4\u5408，\u518d\u8df3\u8fc7\u65b0\u7684\u5de6\u53f3\u6307\u9488\u4e0e\u521a\u4f7f\u7528\u503c\u76f8\u540c\u7684\u5143\u7d20\u3002<\/p>\n
\u6392\u5e8f\u8fd8\u6709\u4e00\u4e2a\u989d\u5916\u4f5c\u7528：\u5982\u679c nums[i] > 0，\u90a3\u4e48\u540e\u9762\u7684\u6570\u4e5f\u90fd\u5927\u4e8e\u96f6，\u4e09\u6570\u548c\u4e0d\u53ef\u80fd\u518d\u56de\u5230\u96f6，\u53ef\u4ee5\u63d0\u524d\u7ed3\u675f\u5916\u5c42\u5faa\u73af\u3002<\/p>\n
Java\u4ee3\u7801<\/p>\n
import java.util.ArrayList;
\nimport java.util.Arrays;
\nimport java.util.List;<\/p>\n
class Solution {
\n public List<List<Integer>> threeSum(int[] nums) {
\n Arrays.sort(nums);
\n List<List<Integer>> ret = new ArrayList<>();<\/p>\n
for (int i = 0; i < nums.length – 2; i++) {
\n if (i > 0 && nums[i] == nums[i – 1]) {
\n continue;
\n }
\n if (nums[i] > 0) {
\n break;
\n }<\/p>\n
int left = i + 1;
\n int right = nums.length – 1;<\/p>\n
while (left < right) {
\n int sum = nums[i] + nums[left] + nums[right];<\/p>\n
if (sum < 0) {
\n left++;
\n } else if (sum > 0) {
\n right–;
\n } else {
\n ret.add(Arrays.asList(nums[i], nums[left], nums[right]));
\n left++;
\n right–;<\/p>\n
while (left < right && nums[left] == nums[left – 1]) {
\n left++;
\n }
\n while (left < right && nums[right] == nums[right + 1]) {
\n right–;
\n }
\n }
\n }
\n }<\/p>\n
return ret;
\n }
\n}<\/p>\n
\u4ee3\u7801\u8bf4\u660e<\/p>\n
\u6392\u5e8f\u540e，\u4e09\u5143\u7ec4\u4f1a\u4ee5\u975e\u9012\u51cf\u987a\u5e8f\u51fa\u73b0，\u56e0\u6b64\u76f8\u540c\u7b54\u6848\u4e2d\u7684\u6570\u5b57\u6392\u5217\u4e5f\u7edf\u4e00\u4e86\u3002\u5916\u5c42\u5faa\u73af\u53ea\u9700\u8981\u4fdd\u8bc1 i \u53f3\u8fb9\u8fd8\u6709\u4e24\u4e2a\u4f4d\u7f6e，\u6240\u4ee5\u6761\u4ef6\u662f i < nums.length – 2\u3002<\/p>\n
i > 0 && nums[i] == nums[i – 1] \u53ea\u8df3\u8fc7\u540c\u4e00\u5c42\u4e2d\u8fde\u7eed\u91cd\u590d\u7684\u56fa\u5b9a\u503c，\u4e0d\u4f1a\u5f71\u54cd\u4f7f\u7528\u91cd\u590d\u6570\u5b57\u7ec4\u6210\u5408\u6cd5\u7b54\u6848\u3002\u6bd4\u5982\u6392\u5e8f\u540e\u7684 [-1, -1, 0, 1, 2]，\u7b2c\u4e00\u4e2a -1 \u5df2\u7ecf\u4f5c\u4e3a\u56fa\u5b9a\u503c\u641c\u7d22\u8fc7，\u7b2c\u4e8c\u4e2a -1 \u4f5c\u4e3a\u56fa\u5b9a\u503c\u65f6\u4f1a\u5f97\u5230\u540c\u6837\u7684\u7b54\u6848，\u56e0\u6b64\u8df3\u8fc7\u3002<\/p>\n
\u5728\u5de6\u53f3\u626b\u63cf\u4e2d，\u548c\u504f\u5c0f\u65f6\u5de6\u6307\u9488\u53f3\u79fb，\u548c\u504f\u5927\u65f6\u53f3\u6307\u9488\u5de6\u79fb\u3002\u547d\u4e2d\u7b54\u6848\u540e\u5fc5\u987b\u540c\u65f6\u79fb\u52a8\u4e24\u4e2a\u6307\u9488，\u5426\u5219\u4e0b\u4e00\u8f6e\u8fd8\u4f1a\u505c\u5728\u540c\u4e00\u7ec4\u6570\u4e0a\u3002\u79fb\u52a8\u540e\u518d\u8df3\u8fc7\u76f8\u540c\u503c，\u624d\u80fd\u907f\u514d [0, 0, 0, 0] \u4e4b\u7c7b\u7684\u6570\u636e\u4ea7\u751f\u91cd\u590d\u4e09\u5143\u7ec4\u3002<\/p>\n
\u590d\u6742\u5ea6\u4e0e\u6613\u9519\u70b9<\/p>\n
\u6613\u9519\u70b9\u5305\u62ec：<\/p>\n
\u9898\u76ee\u63cf\u8ff0<\/p>\n
\u7ed9\u5b9a\u4e00\u4e2a\u6574\u6570\u6570\u7ec4 nums \u548c\u76ee\u6807\u503c target，\u627e\u51fa\u6240\u6709\u603b\u548c\u7b49\u4e8e target \u4e14\u4e0d\u91cd\u590d\u7684\u56db\u5143\u7ec4 [nums[i], nums[j], nums[left], nums[right]]\u3002\u56db\u4e2a\u5143\u7d20\u5fc5\u987b\u6765\u81ea\u56db\u4e2a\u4e0d\u540c\u4e0b\u6807\u3002<\/p>\n
\u4f8b\u5982，\u8f93\u5165 nums = [1, 0, -1, 0, -2, 2]\u3001target = 0，\u7ed3\u679c\u4e3a [[-2, -1, 1, 2], [-2, 0, 0, 2], [-1, 0, 0, 1]]\u3002<\/p>\n
\u9898\u76ee\u94fe\u63a5<\/p>\n
LeetCode 18. \u56db\u6570\u4e4b\u548c<\/p>\n
\u7b97\u6cd5\u601d\u8def<\/p>\n
\u56db\u6570\u4e4b\u548c\u53ef\u4ee5\u770b\u6210\u4e09\u6570\u4e4b\u548c\u518d\u589e\u52a0\u4e00\u5c42\u56fa\u5b9a\u4e0b\u6807：\u5148\u6392\u5e8f，\u7528 i \u56fa\u5b9a\u7b2c\u4e00\u4e2a\u6570，\u7528 j \u56fa\u5b9a\u7b2c\u4e8c\u4e2a\u6570，\u518d\u7528 left \u548c right \u5728\u5269\u4f59\u533a\u95f4\u4e2d\u8fdb\u884c\u76f8\u5411\u626b\u63cf\u3002<\/p>\n
\u6d41\u7a0b\u662f：<\/p>\n
\u8fd9\u91cc\u5fc5\u987b\u4f7f\u7528 long \u8ba1\u7b97 sum\u3002\u5373\u4f7f\u65b9\u6cd5\u53c2\u6570\u548c\u6570\u7ec4\u5143\u7d20\u662f int，\u56db\u4e2a\u63a5\u8fd1 1_000_000_000 \u7684\u6570\u76f8\u52a0\u4e5f\u53ef\u80fd\u8d85\u8fc7 int \u7684\u6700\u5927\u503c\u3002\u9700\u8981\u5728\u52a0\u6cd5\u5f00\u59cb\u524d\u8f6c\u6362\u7c7b\u578b：(long) nums[i] + nums[j] + nums[left] + nums[right]\u3002\u5982\u679c\u53ea\u628a\u6700\u7ec8\u7ed3\u679c\u8d4b\u503c\u7ed9 long，\u800c\u52a0\u6cd5\u8fc7\u7a0b\u4ecd\u5168\u90e8\u662f int，\u6ea2\u51fa\u5df2\u7ecf\u53d1\u751f，\u540e\u7eed\u518d\u8f6c\u6362\u4e5f\u65e0\u6cd5\u6062\u590d\u3002<\/p>\n
\u56db\u5c42\u53bb\u91cd\u5206\u522b\u5bf9\u5e94：<\/p>\n
Java\u4ee3\u7801<\/p>\n
import java.util.ArrayList;
\nimport java.util.Arrays;
\nimport java.util.List;<\/p>\n
class Solution {
\n public List<List<Integer>> fourSum(int[] nums, int target) {
\n Arrays.sort(nums);
\n List<List<Integer>> ret = new ArrayList<>();<\/p>\n
for (int i = 0; i < nums.length – 3; i++) {
\n if (i > 0 && nums[i] == nums[i – 1]) {
\n continue;
\n }<\/p>\n
for (int j = i + 1; j < nums.length – 2; j++) {
\n if (j > i + 1 && nums[j] == nums[j – 1]) {
\n continue;
\n }<\/p>\n
int left = j + 1;
\n int right = nums.length – 1;<\/p>\n
while (left < right) {
\n long sum = (long) nums[i] + nums[j]
\n + nums[left] + nums[right];<\/p>\n
if (sum < target) {
\n left++;
\n } else if (sum > target) {
\n right–;
\n } else {
\n ret.add(Arrays.asList(
\n nums[i], nums[j], nums[left], nums[right]));
\n left++;
\n right–;<\/p>\n
while (left < right && nums[left] == nums[left – 1]) {
\n left++;
\n }
\n while (left < right && nums[right] == nums[right + 1]) {
\n right–;
\n }
\n }
\n }
\n }
\n }<\/p>\n
return ret;
\n }
\n}<\/p>\n
\u4ee3\u7801\u8bf4\u660e<\/p>\n
\u5916\u5c42 i \u53f3\u4fa7\u81f3\u5c11\u8981\u5269\u4e0b\u4e09\u4e2a\u5143\u7d20，\u6240\u4ee5\u5faa\u73af\u6761\u4ef6\u662f i < nums.length – 3\u3002\u5185\u5c42 j \u53f3\u4fa7\u81f3\u5c11\u8981\u5269\u4e0b\u4e24\u4e2a\u5143\u7d20，\u6240\u4ee5\u6761\u4ef6\u662f j < nums.length – 2\u3002<\/p>\n
j \u7684\u53bb\u91cd\u6761\u4ef6\u4e0d\u80fd\u7b80\u5355\u5199\u6210 j > 0\u3002\u5f53 j == i + 1 \u65f6，\u5b83\u662f\u5f53\u524d\u56fa\u5b9a\u7684 i \u540e\u9762\u7b2c\u4e00\u4e2a\u5019\u9009\u4f4d\u7f6e，\u5373\u4f7f\u6570\u503c\u4e0e\u524d\u9762\u5176\u4ed6\u4f4d\u7f6e\u76f8\u540c，\u4e5f\u4e0d\u80fd\u8de8\u8d8a\u5f53\u524d i \u7684\u8fb9\u754c\u53bb\u8df3\u8fc7\u3002\u6b63\u786e\u7684\u5224\u65ad\u662f j > i + 1 && nums[j] == nums[j – 1]，\u8868\u793a\u53ea\u8df3\u8fc7\u540c\u4e00\u4e2a i \u4e0b\u5df2\u7ecf\u5904\u7406\u8fc7\u7684\u7b2c\u4e8c\u4e2a\u6570\u3002<\/p>\n
\u76f8\u5411\u626b\u63cf\u90e8\u5206\u548c\u4e09\u6570\u4e4b\u548c\u76f8\u540c：\u548c\u5c0f\u5c31\u9700\u8981\u589e\u5927\u5de6\u4fa7\u6570\u5b57，\u548c\u5927\u5c31\u9700\u8981\u51cf\u5c0f\u53f3\u4fa7\u6570\u5b57\u3002\u547d\u4e2d\u540e\u540c\u65f6\u79fb\u52a8\u5de6\u53f3\u6307\u9488，\u518d\u8df3\u8fc7\u91cd\u590d\u6570\u503c\u3002<\/p>\n
\u56db\u4e2a\u4e0b\u6807\u59cb\u7ec8\u6ee1\u8db3 i < j < left < right，\u6240\u4ee5\u4e0d\u4f1a\u91cd\u590d\u4f7f\u7528\u540c\u4e00\u4e2a\u6570\u7ec4\u4f4d\u7f6e\u3002\u6392\u5e8f\u540e\u52a0\u5165\u7ed3\u679c\u7684\u56db\u4e2a\u6570\u5929\u7136\u662f\u975e\u9012\u51cf\u987a\u5e8f，\u7b54\u6848\u7684\u8868\u793a\u4e5f\u7edf\u4e00\u4e86\u3002<\/p>\n
\u590d\u6742\u5ea6\u4e0e\u6613\u9519\u70b9<\/p>\n
\u6613\u9519\u70b9\u5305\u62ec：<\/p>\n
283 \u79fb\u52a8\u96f6\u4e2d\u7684\u4e24\u4e2a\u6307\u9488\u90fd\u4ece\u5de6\u5411\u53f3，\u4f46\u4e00\u4e2a\u8d1f\u8d23\u8bfb\u53d6\u3001\u4e00\u4e2a\u8d1f\u8d23\u5199\u5165；202 \u5feb\u4e50\u6570\u4e2d\u7684\u4e24\u4e2a\u6307\u9488\u4e5f\u90fd\u6cbf\u7740\u540c\u4e00\u6761\u72b6\u6001\u8def\u7ebf\u524d\u8fdb，\u4f46\u4e00\u4e2a\u8d70\u4e00\u6b65\u3001\u4e00\u4e2a\u8d70\u4e24\u6b65；1089 \u590d\u5199\u96f6\u5219\u662f\u4ece\u53f3\u5411\u5de6\u5b8c\u6210\u8bfb\u5199\u3002<\/p>\n
\u6240\u4ee5\u6211\u73b0\u5728\u4e0d\u518d\u53ea\u6309\u53d8\u91cf\u540d\u8bb0\u5fc6\u201c\u5feb\u6162\u6307\u9488\u201d，\u800c\u662f\u5148\u95ee\u4e24\u4e2a\u6307\u9488\u5404\u81ea\u4ee3\u8868\u4ec0\u4e48：<\/p>\n
\u6307\u9488\u7684\u79fb\u52a8\u65b9\u5411\u548c\u901f\u5ea6，\u90fd\u662f\u7531\u8fd9\u4e2a\u804c\u8d23\u51b3\u5b9a\u7684\u3002<\/p>\n
LCR 179 \u4e2d，\u6570\u7ec4\u6709\u5e8f\u4f7f\u5f97\u201c\u548c\u5c0f\u589e\u5927\u5de6\u7aef\u3001\u548c\u5927\u51cf\u5c0f\u53f3\u7aef\u201d\u6210\u7acb；11 \u76db\u6700\u591a\u6c34\u7684\u5bb9\u5668\u4e2d，\u77ed\u677f\u548c\u5bbd\u5ea6\u7684\u5173\u7cfb\u4f7f\u5f97\u79fb\u52a8\u957f\u8fb9\u6ca1\u6709\u673a\u4f1a\u8d85\u8fc7\u5f53\u524d\u9762\u79ef；611 \u6709\u6548\u4e09\u89d2\u5f62\u7684\u4e2a\u6570\u4e2d，\u6392\u5e8f\u540e\u7684\u4e0d\u7b49\u5f0f\u8ba9\u4e00\u6b21\u5224\u65ad\u80fd\u591f\u6279\u91cf\u8ba1\u6570\u3002<\/p>\n
\u56e0\u6b64，\u770b\u5230\u4e24\u4e2a\u8fb9\u754c\u5e76\u4e0d\u610f\u5473\u7740\u4e00\u5b9a\u80fd\u7528\u53cc\u6307\u9488\u3002\u9700\u8981\u8fdb\u4e00\u6b65\u786e\u8ba4：\u79fb\u52a8\u4e00\u4fa7\u540e，\u662f\u5426\u771f\u7684\u80fd\u6392\u9664\u4e00\u6279\u5019\u9009，\u5e76\u4e14\u4e0d\u4f1a\u9519\u8fc7\u7b54\u6848\u3002<\/p>\n
611\u300115\u300118 \u90fd\u5148\u6392\u5e8f，\u4f46\u4f7f\u7528\u6392\u5e8f\u7684\u65b9\u5f0f\u4e0d\u5b8c\u5168\u76f8\u540c：<\/p>\n
\u6392\u5e8f\u8fd8\u4f1a\u6539\u53d8\u8f93\u5165\u6570\u7ec4\u539f\u6765\u7684\u987a\u5e8f，\u8fd9\u4e9b\u9898\u7684\u9898\u610f\u5141\u8bb8\u8fd9\u79cd\u53d8\u5316\u3002\u82e5\u9898\u76ee\u8981\u6c42\u4fdd\u7559\u539f\u6570\u7ec4\u987a\u5e8f，\u5c31\u9700\u8981\u91cd\u65b0\u8003\u8651\u662f\u5426\u53ef\u4ee5\u6392\u5e8f\u3002<\/p>\n
\u5728\u4e09\u6570\u4e4b\u548c\u548c\u56db\u6570\u4e4b\u548c\u4e2d，\u76f8\u540c\u6570\u503c\u6765\u81ea\u4e0d\u540c\u4e0b\u6807\u65f6\u4ecd\u7136\u53ef\u80fd\u7ec4\u6210\u5408\u6cd5\u7b54\u6848\u3002\u4f8b\u5982\u4e24\u4e2a 0 \u53ef\u4ee5\u540c\u65f6\u53c2\u4e0e\u4e00\u4e2a\u7b54\u6848\u3002\u53bb\u91cd\u9488\u5bf9\u7684\u662f\u201c\u540c\u4e00\u4e2a\u503c\u7ec4\u5408\u5df2\u7ecf\u88ab\u8bb0\u5f55\u8fc7\u201d，\u800c\u4e0d\u662f\u628a\u91cd\u590d\u5143\u7d20\u5168\u90e8\u5220\u9664\u3002<\/p>\n
611 \u5219\u4e0d\u540c，\u56e0\u4e3a\u5b83\u7edf\u8ba1\u4e0b\u6807\u7ec4\u5408\u7684\u6570\u91cf，\u76f8\u540c\u8fb9\u957f\u5bf9\u5e94\u4e0d\u540c\u4e0b\u6807\u65f6\u9700\u8981\u5206\u522b\u8ba1\u6570，\u4e0d\u80fd\u4f7f\u7528\u4e09\u6570\u4e4b\u548c\u7684\u53bb\u91cd\u65b9\u5f0f\u3002<\/p>\n
18 \u56db\u6570\u4e4b\u548c\u4e2d，\u6307\u9488\u65b9\u5411\u672c\u8eab\u6ca1\u6709\u95ee\u9898，\u4f46\u5982\u679c\u56db\u4e2a int \u5148\u76f8\u52a0\u5e76\u6ea2\u51fa，sum \u7684\u5927\u5c0f\u5c31\u4f1a\u53d8\u9519，\u540e\u9762\u7684\u79fb\u52a8\u4e5f\u4f1a\u8ddf\u7740\u9519\u3002\u4f7f\u7528 long \u65f6，\u7c7b\u578b\u8f6c\u6362\u5fc5\u987b\u53d1\u751f\u5728\u7b2c\u4e00\u6b21\u52a0\u6cd5\u4e4b\u524d\u3002<\/p>\n
\u8fd9\u63d0\u9192\u6211，\u7b97\u6cd5\u903b\u8f91\u548c Java \u7c7b\u578b\u8303\u56f4\u9700\u8981\u4e00\u8d77\u68c0\u67e5\u3002\u4ee3\u7801\u770b\u8d77\u6765\u7b26\u5408\u53cc\u6307\u9488\u6a21\u677f，\u5e76\u4e0d\u4ee3\u8868\u5728\u6240\u6709\u6570\u503c\u8303\u56f4\u4e0b\u90fd\u5b89\u5168\u3002<\/p>\n
\u73b0\u5728\u9047\u5230\u4e00\u4e2a\u53ef\u80fd\u4f7f\u7528\u53cc\u6307\u9488\u7684\u95ee\u9898\u65f6，\u6211\u4f1a\u6309\u4e0b\u9762\u7684\u987a\u5e8f\u5224\u65ad：<\/p>\n
\u8fd9\u516b\u9053\u9898\u653e\u5728\u4e00\u8d77\u540e，\u53cc\u6307\u9488\u5bf9\u6211\u4eec\u6765\u8bf4\u4e0d\u518d\u662f\u5355\u72ec\u7684\u4e00\u7ec4\u56fa\u5b9a\u4ee3\u7801，\u800c\u662f\u4e00\u79cd\u5229\u7528\u804c\u8d23\u3001\u987a\u5e8f\u3001\u5355\u8c03\u6027\u548c\u6392\u9664\u5173\u7cfb\u6765\u51cf\u5c11\u91cd\u590d\u641c\u7d22\u7684\u65b9\u6cd5\u3002\u4ee3\u7801\u4e2d\u7684 left++\u3001right– \u6216 slow++ \u53ea\u6709\u5728\u79fb\u52a8\u7406\u7531\u6e05\u695a\u65f6\u624d\u771f\u6b63\u53ef\u9760\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
\u5f15\u5165：\u53cc\u6307\u9488\u5230\u5e95\u89e3\u51b3\u4ec0\u4e48\u95ee\u9898
\n\u6211\u76ee\u524d\u5bf9\u201c\u53cc\u6307\u9488\u201d\u7684\u7406\u89e3\u662f：\u5728\u904d\u5386\u6570\u7ec4\u3001\u6570\u5b57\u72b6\u6001\u6216\u5019\u9009\u533a\u95f4\u65f6，\u540c\u65f6\u7ef4\u62a4\u4e24\u4e2a\u4f1a\u79fb\u52a8\u7684\u4f4d\u7f6e，\u5e76\u8ba9\u5b83\u4eec\u627f\u62c5\u4e0d\u540c\u7684\u804c\u8d23\u3002\u8fd9\u6837\u505a\u7684\u4ef7\u503c\u4e0d\u53ea\u662f\u4ee3\u7801\u91cc\u51fa\u73b0\u4e86\u4e24\u4e2a\u53d8\u91cf，\u800c\u662f\u6bcf\u6b21\u79fb\u52a8\u90fd\u80fd\u6839\u636e\u9898\u76ee\u7684\u89c4\u5f8b\u6392\u9664\u4e00\u6279\u4e0d\u53ef\u80fd\u7684\u60c5\u51b5，\u4ece\u800c\u51cf\u5c11\u91cd\u590d\u679a\u4e3e\u3002
\n\u5f88\u591a\u76f4\u63a5\u679a\u4e3e\u7684\u5199\u6cd5\u4f1a\u4ea7\u751f\u4e24\u5c42\u3001\u4e09\u5c42\u751a\u81f3\u56db\u5c42\u5faa\u73af\u3002\u53cc\u6307\u9488\u5e76\u4e0d\u80fd\u628a\u6240\u6709\u95ee\u9898\u90fd\u53d8\u6210\u7ebf\u6027\u590d\u6742\u5ea6，\u4f46\u5728\u6570\u636e\u6709\u5e8f\u3001\u7ed3\u679c\u5177\u6709\u5355\u8c03\u6027<\/p>\n","protected":false},"author":2,"featured_media":99261,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[99,2692,1813,305,427],"topic":[],"class_list":["post-99262","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-server","tag-java","tag-leetcode","tag-1813","tag-305","tag-427"],"yoast_head":"\n