![\"\"](\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/01\/20260120054212-696f15b486238.png\")
<\/p>\n\u6ee1\u4e8c\u53c9\u6811：\u5982\u679c\u4e00\u68f5\u4e8c\u53c9\u6811\u53ea\u6709\u5ea6\u4e3a0\u7684\u7ed3\u70b9\u548c\u5ea6\u4e3a2\u7684\u7ed3\u70b9，\u5e76\u4e14\u5ea6\u4e3a0\u7684\u7ed3\u70b9\u5728\u540c\u4e00\u5c42\u4e0a，\u5219\u8fd9\u68f5\u4e8c\u53c9\u6811\u4e3a\u6ee1\u4e8c\u53c9\u6811\u3002<\/p>\n
\u5982\u56fe\u6240\u793a：<\/p>\n<\/p>\n
<\/p>\n
\u8fd9\u68f5\u4e8c\u53c9\u6811\u4e3a\u6ee1\u4e8c\u53c9\u6811，\u4e5f\u53ef\u4ee5\u8bf4\u6df1\u5ea6\u4e3ak，\u67092^k-1\u4e2a\u8282\u70b9\u7684\u4e8c\u53c9\u6811\u3002<\/p>\n
\u4ec0\u4e48\u662f\u5b8c\u5168\u4e8c\u53c9\u6811？<\/p>\n
\u5b8c\u5168\u4e8c\u53c9\u6811\u7684\u5b9a\u4e49\u5982\u4e0b：\u5728\u5b8c\u5168\u4e8c\u53c9\u6811\u4e2d，\u9664\u4e86\u6700\u5e95\u5c42\u8282\u70b9\u53ef\u80fd\u6ca1\u586b\u6ee1\u5916，\u5176\u4f59\u6bcf\u5c42\u8282\u70b9\u6570\u90fd\u8fbe\u5230\u6700\u5927\u503c，\u5e76\u4e14\u6700\u4e0b\u9762\u4e00\u5c42\u7684\u8282\u70b9\u90fd\u96c6\u4e2d\u5728\u8be5\u5c42\u6700\u5de6\u8fb9\u7684\u82e5\u5e72\u4f4d\u7f6e\u3002\u82e5\u6700\u5e95\u5c42\u4e3a\u7b2c h \u5c42（h\u4ece1\u5f00\u59cb），\u5219\u8be5\u5c42\u5305\u542b 1~ 2^(h-1) \u4e2a\u8282\u70b9\u3002<\/p>\n
\u524d\u9762\u4ecb\u7ecd\u7684\u6811，\u90fd\u6ca1\u6709\u6570\u503c\u7684，\u800c\u4e8c\u53c9\u641c\u7d22\u6811\u662f\u6709\u6570\u503c\u7684\u4e86，\u4e8c\u53c9\u641c\u7d22\u6811\u662f\u4e00\u4e2a\u6709\u5e8f\u6811\u3002<\/p>\n
\u5e73\u8861\u4e8c\u53c9\u641c\u7d22\u6811：\u53c8\u88ab\u79f0\u4e3aAVL（Adelson-Velsky and Landis）\u6811，\u4e14\u5177\u6709\u4ee5\u4e0b\u6027\u8d28：\u5b83\u662f\u4e00\u68f5\u7a7a\u6811\u6216\u5b83\u7684\u5de6\u53f3\u4e24\u4e2a\u5b50\u6811\u7684\u9ad8\u5ea6\u5dee\u7684\u7edd\u5bf9\u503c\u4e0d\u8d85\u8fc71，\u5e76\u4e14\u5de6\u53f3\u4e24\u4e2a\u5b50\u6811\u90fd\u662f\u4e00\u68f5\u5e73\u8861\u4e8c\u53c9\u6811\u3002<\/p>\n
\u5982\u56fe：<\/p>\n<\/p>\n
![\"\"](\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/01\/20260120054212-696f15b4b776f.png\")
<\/p>\n<\/p>\n
![\"\"](\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/01\/20260120054212-696f15b4e4fbd.png\")
<\/p>\n
![\"\"](\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/01\/20260120054213-696f15b57f904.png\")
<\/p>\n
\u5982\u679c\u7236\u8282\u70b9\u7684\u6570\u7ec4\u4e0b\u6807\u662f i，\u90a3\u4e48\u5b83\u7684\u5de6\u5b69\u5b50\u5c31\u662f i * 2 + 1，\u53f3\u5b69\u5b50\u5c31\u662f i * 2 + 2\u3002<\/p>\n<\/p>\n
\u4e8c\u53c9\u6811\u4e3b\u8981\u6709\u4e24\u79cd\u904d\u5386\u65b9\u5f0f：<\/p>\n
\u4e00\u822c\u91c7\u7528\u9012\u5f52\u6765\u5b9e\u73b0，\u800c\u6808\u662f\u5b9e\u73b0\u9012\u5f52\u7684\u4e00\u79cd\u5e38\u7528\u7ed3\u6784<\/p>\n<\/p>\n
\u4e00\u822c\u91c7\u7528\u961f\u5217\u6765\u5b9e\u73b0<\/p>\n<\/p>\n
public class TreeNode {
\n int val;
\n TreeNode left;
\n TreeNode right;<\/p>\n
TreeNode() {}
\n TreeNode(int val) { this.val = val; }
\n TreeNode(int val, TreeNode left, TreeNode right) {
\n this.val = val;
\n this.left = left;
\n this.right = right;
\n }
\n} <\/p>\n
\u4e09\u79cd\u6784\u9020\u65b9\u6cd5，\u5206\u522b\u662f\u5565\u90fd\u4e0d\u4f20，\u53ea\u4f20\u8282\u70b9\u503c，\u4f20\u8282\u70b9\u503c\u548c\u5de6\u53f3\u6307\u9488\u6307\u5411<\/p>\n
\u9898\u76ee\u94fe\u63a5\/\u6587\u7ae0\u8bb2\u89e3\/\u89c6\u9891\u8bb2\u89e3：<\/span>https:\/\/programmercarl.com\/%E4%BA%8C%E5%8F%89%E6%A0%91%E7%9A%84%E9%80%92%E5%BD%92%E9%81%8D%E5%8E%86.html<\/p>\n \u9012\u5f52\u7b97\u6cd5\u7684\u4e09\u4e2a\u8981\u7d20，\u6bcf\u6b21\u5199\u9012\u5f52，\u90fd\u6309\u7167\u8fd9\u4e09\u8981\u7d20\u6765\u5199，\u53ef\u4ee5\u4fdd\u8bc1\u5199\u51fa\u6b63\u786e\u7684\u9012\u5f52\u7b97\u6cd5！<\/p>\n \u786e\u5b9a\u9012\u5f52\u51fd\u6570\u7684\u53c2\u6570\u548c\u8fd4\u56de\u503c：\u00a0\u786e\u5b9a\u54ea\u4e9b\u53c2\u6570\u662f\u9012\u5f52\u7684\u8fc7\u7a0b\u4e2d\u9700\u8981\u5904\u7406\u7684，\u90a3\u4e48\u5c31\u5728\u9012\u5f52\u51fd\u6570\u91cc\u52a0\u4e0a\u8fd9\u4e2a\u53c2\u6570， \u5e76\u4e14\u8fd8\u8981\u660e\u786e\u6bcf\u6b21\u9012\u5f52\u7684\u8fd4\u56de\u503c\u662f\u4ec0\u4e48\u8fdb\u800c\u786e\u5b9a\u9012\u5f52\u51fd\u6570\u7684\u8fd4\u56de\u7c7b\u578b\u3002<\/p>\n<\/li>\n \u786e\u5b9a\u7ec8\u6b62\u6761\u4ef6：\u00a0\u5199\u5b8c\u4e86\u9012\u5f52\u7b97\u6cd5, \u8fd0\u884c\u7684\u65f6\u5019，\u7ecf\u5e38\u4f1a\u9047\u5230\u6808\u6ea2\u51fa\u7684\u9519\u8bef，\u5c31\u662f\u6ca1\u5199\u7ec8\u6b62\u6761\u4ef6\u6216\u8005\u7ec8\u6b62\u6761\u4ef6\u5199\u7684\u4e0d\u5bf9，\u64cd\u4f5c\u7cfb\u7edf\u4e5f\u662f\u7528\u4e00\u4e2a\u6808\u7684\u7ed3\u6784\u6765\u4fdd\u5b58\u6bcf\u4e00\u5c42\u9012\u5f52\u7684\u4fe1\u606f，\u5982\u679c\u9012\u5f52\u6ca1\u6709\u7ec8\u6b62，\u64cd\u4f5c\u7cfb\u7edf\u7684\u5185\u5b58\u6808\u5fc5\u7136\u5c31\u4f1a\u6ea2\u51fa\u3002<\/p>\n<\/li>\n \u786e\u5b9a\u5355\u5c42\u9012\u5f52\u7684\u903b\u8f91：\u00a0\u786e\u5b9a\u6bcf\u4e00\u5c42\u9012\u5f52\u9700\u8981\u5904\u7406\u7684\u4fe1\u606f\u3002\u5728\u8fd9\u91cc\u4e5f\u5c31\u4f1a\u91cd\u590d\u8c03\u7528\u81ea\u5df1\u6765\u5b9e\u73b0\u9012\u5f52\u7684\u8fc7\u7a0b\u3002<\/p>\n<\/li>\n \/\/ \u524d\u5e8f\u904d\u5386\u00b7\u9012\u5f52\u00b7LC144_\u4e8c\u53c9\u6811\u7684\u524d\u5e8f\u904d\u5386 public void preorder(TreeNode root, List<Integer> result) { void inorder(TreeNode root, List<Integer> list) { void postorder(TreeNode root, List<Integer> list) { \u7ed9\u4f60\u4e8c\u53c9\u6811\u7684\u6839\u8282\u70b9\u00a0root\u00a0，\u8fd4\u56de\u5b83\u8282\u70b9\u503c\u7684\u00a0\u524d\u5e8f\u00a0\u904d\u5386\u3002<\/p>\n<\/p>\n \u793a\u4f8b 1：<\/p>\n \u8f93\u5165：root = [1,null,2,3]<\/p>\n \u8f93\u51fa：[1,2,3]<\/p>\n \u89e3\u91ca：<\/p>\n<\/p>\n \u793a\u4f8b 2：<\/p>\n \u8f93\u5165：root = [1,2,3,4,5,null,8,null,null,6,7,9]<\/p>\n \u8f93\u51fa：[1,2,4,5,6,7,3,8,9]<\/p>\n \u89e3\u91ca：<\/p>\n<\/p>\n \u793a\u4f8b 3：<\/p>\n \u8f93\u5165：root = []<\/p>\n \u8f93\u51fa：[]<\/p>\n \u793a\u4f8b 4：<\/p>\n \u8f93\u5165：root = [1]<\/p>\n \u8f93\u51fa：[1]<\/p>\n<\/p>\n \/** public void preorder(TreeNode root,List<Integer> list){ \u524d\u5e8f\u904d\u5386\u51b3\u5b9a\u00a0list.add(root.val)\u5728\u6700\u524d<\/p>\n<\/p>\n \u7ed9\u5b9a\u4e00\u4e2a\u4e8c\u53c9\u6811\u7684\u6839\u8282\u70b9\u00a0root\u00a0，\u8fd4\u56de\u00a0\u5b83\u7684\u00a0\u4e2d\u5e8f\u00a0\u904d\u5386\u00a0\u3002<\/p>\n<\/p>\n \u793a\u4f8b 1：<\/p>\n \u8f93\u5165：root = [1,null,2,3] \u793a\u4f8b 2：<\/p>\n \u8f93\u5165：root = [] \u793a\u4f8b 3：<\/p>\n \u8f93\u5165：root = [1] \/** public void inorder(TreeNode root,List<Integer> list){ \u7ed9\u4f60\u4e00\u68f5\u4e8c\u53c9\u6811\u7684\u6839\u8282\u70b9\u00a0root\u00a0，\u8fd4\u56de\u5176\u8282\u70b9\u503c\u7684\u00a0\u540e\u5e8f\u904d\u5386\u00a0\u3002<\/p>\n<\/p>\n \u793a\u4f8b 1：<\/p>\n \u8f93\u5165：root = [1,null,2,3]<\/p>\n \u8f93\u51fa：[3,2,1]<\/p>\n \u89e3\u91ca：<\/p>\n \u793a\u4f8b 2：<\/p>\n \u8f93\u5165：root = [1,2,3,4,5,null,8,null,null,6,7,9]<\/p>\n \u8f93\u51fa：[4,6,7,5,2,9,8,3,1]<\/p>\n \u89e3\u91ca：<\/p>\n \u793a\u4f8b 3：<\/p>\n \u8f93\u5165：root = []<\/p>\n \u8f93\u51fa：[]<\/p>\n \u793a\u4f8b 4：<\/p>\n \u8f93\u5165：root = [1]<\/p>\n \u8f93\u51fa：[1]<\/p>\n \/** public void postorder(TreeNode root,List<Integer> list){ \u9898\u76ee\u94fe\u63a5\/\u6587\u7ae0\u8bb2\u89e3\/\u89c6\u9891\u8bb2\u89e3：<\/span> \u7ed9\u4f60\u4e8c\u53c9\u6811\u7684\u6839\u8282\u70b9\u00a0root\u00a0，\u8fd4\u56de\u5176\u8282\u70b9\u503c\u7684\u00a0\u5c42\u5e8f\u904d\u5386\u00a0\u3002 （\u5373\u9010\u5c42\u5730，\u4ece\u5de6\u5230\u53f3\u8bbf\u95ee\u6240\u6709\u8282\u70b9）\u3002<\/p>\n<\/p>\n \u793a\u4f8b 1：<\/p>\n \u8f93\u5165：root = [3,9,20,null,null,15,7] \u793a\u4f8b 2：<\/p>\n \u8f93\u5165：root = [1] \u793a\u4f8b 3：<\/p>\n \u8f93\u5165：root = [] \/** public List<List<Integer>> levelOrder(TreeNode root) { \u7528\u961f\u5217\u8fdb\u884c\u89e3\u51b3，\u904d\u5386\u4e00\u4e2a\u8282\u70b9，\u5c31\u628a\u8fd9\u4e2a\u8282\u70b9\u5f39\u51fa，\u5e76\u628a\u8fd9\u4e2a\u8282\u70b9\u7684\u5de6\u53f3\u8282\u70b9\u5b58\u5165\u961f\u5217，\u76f4\u5230\u961f\u5217\u4e3a\u7a7a（\u6700\u540e\u5f39\u51fa\u7684\u8282\u70b9\u5de6\u53f3\u8282\u70b9\u90fd\u4e3a\u7a7a）<\/p>\n \u5c31\u662f\u8fd9\u9053\u6bcd\u9898\u4e0d\u518d\u8d58\u8ff0<\/p>\n \u7ed9\u4f60\u4e8c\u53c9\u6811\u7684\u6839\u8282\u70b9\u00a0root\u00a0，\u8fd4\u56de\u5176\u8282\u70b9\u503c\u00a0\u81ea\u5e95\u5411\u4e0a\u7684\u5c42\u5e8f\u904d\u5386\u00a0\u3002 （\u5373\u6309\u4ece\u53f6\u5b50\u8282\u70b9\u6240\u5728\u5c42\u5230\u6839\u8282\u70b9\u6240\u5728\u7684\u5c42，\u9010\u5c42\u4ece\u5de6\u5411\u53f3\u904d\u5386）<\/p>\n<\/p>\n \u793a\u4f8b 1：<\/p>\n \u8f93\u5165：root = [3,9,20,null,null,15,7] \u793a\u4f8b 2：<\/p>\n \u8f93\u5165：root = [1] \u793a\u4f8b 3：<\/p>\n \u8f93\u5165：root = [] \/** \u00a0 \u00a0list.addFirst(templist);\u76f4\u63a5\u5c06\u6bcf\u5c42\u5143\u7d20\u7684\u96c6\u5408\u6dfb\u52a0\u5230list\u96c6\u5408\u7684\u6700\u524d\u9762\u5373\u53ef（\u907f\u514d\u5012\u5e8f\u64cd\u4f5c）<\/p>\n \u7ed9\u5b9a\u4e00\u4e2a\u4e8c\u53c9\u6811\u7684\u00a0\u6839\u8282\u70b9\u00a0root，\u60f3\u8c61\u81ea\u5df1\u7ad9\u5728\u5b83\u7684\u53f3\u4fa7，\u6309\u7167\u4ece\u9876\u90e8\u5230\u5e95\u90e8\u7684\u987a\u5e8f，\u8fd4\u56de\u4ece\u53f3\u4fa7\u6240\u80fd\u770b\u5230\u7684\u8282\u70b9\u503c\u3002<\/p>\n<\/p>\n \u793a\u4f8b 1：<\/p>\n \u8f93\u5165：root = [1,2,3,null,5,null,4]<\/p>\n \u8f93\u51fa：[1,3,4]<\/p>\n \u89e3\u91ca：<\/p>\n<\/p>\n \u793a\u4f8b 2：<\/p>\n \u8f93\u5165：root = [1,2,3,4,null,null,null,5]<\/p>\n \u8f93\u51fa：[1,3,4,5]<\/p>\n \u89e3\u91ca：<\/p>\n<\/p>\n \u793a\u4f8b 3：<\/p>\n \u8f93\u5165：root = [1,null,3]<\/p>\n \u8f93\u51fa：[1,3]<\/p>\n \u793a\u4f8b 4：<\/p>\n \u8f93\u5165：root = []<\/p>\n \u8f93\u51fa：[]<\/p>\n \/** \u5176\u5b9e\u5c31\u662f\u628a\u6bcf\u5c42\u5143\u7d20\u96c6\u5408\u4e2d\u7684\u6700\u540e\u4e00\u4e2a\u5143\u7d20\u6dfb\u52a0\u5230list\u96c6\u5408\u4e2d\u5c31\u884c<\/p>\n \u7ed9\u5b9a\u4e00\u4e2a\u975e\u7a7a\u4e8c\u53c9\u6811\u7684\u6839\u8282\u70b9\u00a0root\u00a0, \u4ee5\u6570\u7ec4\u7684\u5f62\u5f0f\u8fd4\u56de\u6bcf\u4e00\u5c42\u8282\u70b9\u7684\u5e73\u5747\u503c\u3002\u4e0e\u5b9e\u9645\u7b54\u6848\u76f8\u5dee\u00a010-5\u00a0\u4ee5\u5185\u7684\u7b54\u6848\u53ef\u4ee5\u88ab\u63a5\u53d7\u3002<\/p>\n<\/p>\n \u793a\u4f8b 1：<\/p>\n<\/p>\n \u8f93\u5165：root = [3,9,20,null,null,15,7] \u793a\u4f8b 2:<\/p>\n<\/p>\n \u8f93\u5165：root = [3,9,20,15,7] \/** \u8ba1\u7b97\u6bcf\u5c42\u7684\u5e73\u5747\u503c\u5b58\u5165list\u5373\u53ef<\/p>\n \u7ed9\u5b9a\u4e00\u4e2a N \u53c9\u6811，\u8fd4\u56de\u5176\u8282\u70b9\u503c\u7684\u5c42\u5e8f\u904d\u5386\u3002（\u5373\u4ece\u5de6\u5230\u53f3，\u9010\u5c42\u904d\u5386）\u3002<\/p>\n \u6811\u7684\u5e8f\u5217\u5316\u8f93\u5165\u662f\u7528\u5c42\u5e8f\u904d\u5386，\u6bcf\u7ec4\u5b50\u8282\u70b9\u90fd\u7531 null \u503c\u5206\u9694（\u53c2\u89c1\u793a\u4f8b）\u3002<\/p>\n<\/p>\n \u793a\u4f8b 1：<\/p>\n<\/p>\n \u8f93\u5165：root = [1,null,3,2,4,null,5,6] \u793a\u4f8b 2：<\/p>\n<\/p>\n \u8f93\u5165：root = [1,null,2,3,4,5,null,null,6,7,null,8,null,9,10,null,null,11,null,12,null,13,null,null,14] \/* public Node() {}<\/p>\n public Node(int _val) { public Node(int _val, List<Node> _children) { class Solution { public List<List<Integer>> levelOrder(Node root) { \u5176\u5b9e\u672c\u8d28\u4e0a\u548c\u4e8c\u53c9\u6811\u4e00\u6837，\u4e8c\u53c9\u6811\u662f\u4e24\u4e2a\u5b69\u5b50\u8282\u70b9，N\u53c9\u6811\u662fn\u4e2a\u5b69\u5b50\u8282\u70b9<\/p>\n \u7ed9\u5b9a\u4e00\u68f5\u4e8c\u53c9\u6811\u7684\u6839\u8282\u70b9\u00a0root\u00a0，\u8bf7\u627e\u51fa\u8be5\u4e8c\u53c9\u6811\u4e2d\u6bcf\u4e00\u5c42\u7684\u6700\u5927\u503c\u3002<\/p>\n<\/p>\n \u793a\u4f8b1：<\/p>\n<\/p>\n \u8f93\u5165: root = [1,3,2,5,3,null,9] \u793a\u4f8b2：<\/p>\n \u8f93\u5165: root = [1,2,3] \/** \u6bcf\u5c42\u5143\u7d20\u627e\u51fa\u6700\u5927\u503c，\u7136\u540e\u628a\u6700\u5927\u503c\u5b58\u5165list\u5c31\u884c<\/p>\n \u7ed9\u5b9a\u4e00\u4e2a\u00a0\u5b8c\u7f8e\u4e8c\u53c9\u6811\u00a0，\u5176\u6240\u6709\u53f6\u5b50\u8282\u70b9\u90fd\u5728\u540c\u4e00\u5c42，\u6bcf\u4e2a\u7236\u8282\u70b9\u90fd\u6709\u4e24\u4e2a\u5b50\u8282\u70b9\u3002\u4e8c\u53c9\u6811\u5b9a\u4e49\u5982\u4e0b：<\/p>\n struct Node { \u586b\u5145\u5b83\u7684\u6bcf\u4e2a next \u6307\u9488，\u8ba9\u8fd9\u4e2a\u6307\u9488\u6307\u5411\u5176\u4e0b\u4e00\u4e2a\u53f3\u4fa7\u8282\u70b9\u3002\u5982\u679c\u627e\u4e0d\u5230\u4e0b\u4e00\u4e2a\u53f3\u4fa7\u8282\u70b9，\u5219\u5c06 next \u6307\u9488\u8bbe\u7f6e\u4e3a\u00a0NULL\u3002<\/p>\n \u521d\u59cb\u72b6\u6001\u4e0b，\u6240\u6709\u00a0next \u6307\u9488\u90fd\u88ab\u8bbe\u7f6e\u4e3a\u00a0NULL\u3002<\/p>\n<\/p>\n \u793a\u4f8b 1：<\/p>\n<\/p>\n \u8f93\u5165：root = [1,2,3,4,5,6,7] \u793a\u4f8b 2:<\/p>\n \u8f93\u5165：root = [] \/* public Node() {}<\/p>\n public Node(int _val) { public Node(int _val, Node _left, Node _right, Node _next) { class Solution { \u770b\u4f3c\u53d8\u4e86，\u5176\u5b9e\u8fd8\u662f\u6ca1\u6709\u53d8，\u53ea\u8981\u628a\u961f\u5217poll\u7684\u6bcf\u4e2a\u8282\u70b9\u7684next\u6307\u5411\u961f\u5217\u7684\u65b0\u961f\u9996（peek）\u5c31\u884c<\/p>\n \u7ed9\u5b9a\u4e00\u4e2a\u4e8c\u53c9\u6811：<\/p>\n struct Node { \u586b\u5145\u5b83\u7684\u6bcf\u4e2a next \u6307\u9488，\u8ba9\u8fd9\u4e2a\u6307\u9488\u6307\u5411\u5176\u4e0b\u4e00\u4e2a\u53f3\u4fa7\u8282\u70b9\u3002\u5982\u679c\u627e\u4e0d\u5230\u4e0b\u4e00\u4e2a\u53f3\u4fa7\u8282\u70b9，\u5219\u5c06 next \u6307\u9488\u8bbe\u7f6e\u4e3a\u00a0NULL\u00a0\u3002<\/p>\n \u521d\u59cb\u72b6\u6001\u4e0b，\u6240\u6709\u00a0next \u6307\u9488\u90fd\u88ab\u8bbe\u7f6e\u4e3a\u00a0NULL\u00a0\u3002<\/p>\n<\/p>\n \u793a\u4f8b 1：<\/p>\n \u8f93\u5165：root = [1,2,3,4,5,null,7] \u793a\u4f8b 2：<\/p>\n \u8f93\u5165：root = [] \/* public Node() {}<\/p>\n public Node(int _val) { public Node(int _val, Node _left, Node _right, Node _next) { class Solution { \u548c\u4e0a\u9762\u90a3\u9898\u4e00\u6837，\u8fde\u4ee3\u7801\u90fd\u4e00\u6837<\/p>\n \u7ed9\u5b9a\u4e00\u4e2a\u4e8c\u53c9\u6811\u00a0root\u00a0，\u8fd4\u56de\u5176\u6700\u5927\u6df1\u5ea6\u3002<\/p>\n \u4e8c\u53c9\u6811\u7684\u00a0\u6700\u5927\u6df1\u5ea6\u00a0\u662f\u6307\u4ece\u6839\u8282\u70b9\u5230\u6700\u8fdc\u53f6\u5b50\u8282\u70b9\u7684\u6700\u957f\u8def\u5f84\u4e0a\u7684\u8282\u70b9\u6570\u3002<\/p>\n<\/p>\n \u793a\u4f8b 1：<\/p>\n<\/p>\n \u8f93\u5165：root = [3,9,20,null,null,15,7] \u793a\u4f8b 2：<\/p>\n \u8f93\u5165：root = [1,null,2] \u53ea\u9700\u8981\u8fd4\u56de\u5faa\u73af\u7684\u6b21\u6570\u5373\u53ef<\/p>\n \u7ed9\u5b9a\u4e00\u4e2a\u4e8c\u53c9\u6811，\u627e\u51fa\u5176\u6700\u5c0f\u6df1\u5ea6\u3002<\/p>\n \u6700\u5c0f\u6df1\u5ea6\u662f\u4ece\u6839\u8282\u70b9\u5230\u6700\u8fd1\u53f6\u5b50\u8282\u70b9\u7684\u6700\u77ed\u8def\u5f84\u4e0a\u7684\u8282\u70b9\u6570\u91cf\u3002<\/p>\n \u8bf4\u660e：\u53f6\u5b50\u8282\u70b9\u662f\u6307\u6ca1\u6709\u5b50\u8282\u70b9\u7684\u8282\u70b9\u3002<\/p>\n<\/p>\n \u793a\u4f8b 1：<\/p>\n \u8f93\u5165：root = [3,9,20,null,null,15,7] \u793a\u4f8b 2：<\/p>\n \u8f93\u5165：root = [2,null,3,null,4,null,5,null,6] \/** \u5c31\u662f\u6dfb\u52a0\u4e00\u4e2areturn，\u7b2c\u4e00\u6b21\u5de6\u53f3\u5b50\u8282\u70b9\u90fd\u662fnull\u7684\u65f6\u5019，return num<\/p>\n","protected":false},"excerpt":{"rendered":" \u4e8c\u53c9\u6811\u7406\u8bba\u57fa\u7840
\nclass Solution {
\n public List<Integer> preorderTraversal(TreeNode root) {
\n List<Integer> result = new ArrayList<Integer>();
\n preorder(root, result);
\n return result;
\n }<\/p>\n
\n if (root == null) {
\n return;
\n }
\n result.add(root.val);
\n preorder(root.left, result);
\n preorder(root.right, result);
\n }
\n}
\n\/\/ \u4e2d\u5e8f\u904d\u5386\u00b7\u9012\u5f52\u00b7LC94_\u4e8c\u53c9\u6811\u7684\u4e2d\u5e8f\u904d\u5386
\nclass Solution {
\n public List<Integer> inorderTraversal(TreeNode root) {
\n List<Integer> res = new ArrayList<>();
\n inorder(root, res);
\n return res;
\n }<\/p>\n
\n if (root == null) {
\n return;
\n }
\n inorder(root.left, list);
\n list.add(root.val); \/\/ \u6ce8\u610f\u8fd9\u4e00\u53e5
\n inorder(root.right, list);
\n }
\n}
\n\/\/ \u540e\u5e8f\u904d\u5386\u00b7\u9012\u5f52\u00b7LC145_\u4e8c\u53c9\u6811\u7684\u540e\u5e8f\u904d\u5386
\nclass Solution {
\n public List<Integer> postorderTraversal(TreeNode root) {
\n List<Integer> res = new ArrayList<>();
\n postorder(root, res);
\n return res;
\n }<\/p>\n
\n if (root == null) {
\n return;
\n }
\n postorder(root.left, list);
\n postorder(root.right, list);
\n list.add(root.val); \/\/ \u6ce8\u610f\u8fd9\u4e00\u53e5
\n }
\n} <\/p>\n\u524d\u5e8f\u904d\u5386<\/h3>\n
![\"\"](\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/01\/20260120054213-696f15b5e5ac2.png\")
<\/p>\n![\"\"](\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/01\/20260120054214-696f15b6173e7.png\")
<\/p>\n
\n * Definition for a binary tree node.
\n * public class TreeNode {
\n * int val;
\n * TreeNode left;
\n * TreeNode right;
\n * TreeNode() {}
\n * TreeNode(int val) { this.val = val; }
\n * TreeNode(int val, TreeNode left, TreeNode right) {
\n * this.val = val;
\n * this.left = left;
\n * this.right = right;
\n * }
\n * }
\n *\/
\nclass Solution {
\n public List<Integer> preorderTraversal(TreeNode root) {
\n List<Integer> list=new ArrayList<>();
\n preorder(root,list);
\n return list;
\n }<\/p>\n
\n if(root==null){
\n return;
\n }
\n list.add(root.val);
\n preorder(root.left,list);
\n preorder(root.right,list);
\n }
\n} <\/p>\n\u4e2d\u5e8f\u904d\u5386<\/h3>\n
![\"\"](\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/01\/20260120054214-696f15b6647d3.jpg\")
<\/p>\n
\n\u8f93\u51fa：[1,3,2]<\/p>\n
\n\u8f93\u51fa：[]<\/p>\n
\n\u8f93\u51fa：[1] <\/p>\n
\n * Definition for a binary tree node.
\n * public class TreeNode {
\n * int val;
\n * TreeNode left;
\n * TreeNode right;
\n * TreeNode() {}
\n * TreeNode(int val) { this.val = val; }
\n * TreeNode(int val, TreeNode left, TreeNode right) {
\n * this.val = val;
\n * this.left = left;
\n * this.right = right;
\n * }
\n * }
\n *\/
\nclass Solution {
\n public List<Integer> inorderTraversal(TreeNode root) {
\n List<Integer> list=new ArrayList<>();
\n inorder(root,list);
\n return list;
\n }<\/p>\n
\n if(root==null){
\n return;
\n }
\n inorder(root.left,list);
\n list.add(root.val);
\n inorder(root.right,list);
\n }
\n} <\/p>\n\u540e\u5e8f\u904d\u5386<\/h3>\n
<\/p>\n<\/p>\n
\n * Definition for a binary tree node.
\n * public class TreeNode {
\n * int val;
\n * TreeNode left;
\n * TreeNode right;
\n * TreeNode() {}
\n * TreeNode(int val) { this.val = val; }
\n * TreeNode(int val, TreeNode left, TreeNode right) {
\n * this.val = val;
\n * this.left = left;
\n * this.right = right;
\n * }
\n * }
\n *\/
\nclass Solution {
\n public List<Integer> postorderTraversal(TreeNode root) {
\n List<Integer> list=new ArrayList<>();
\n postorder(root,list);
\n return list;
\n }<\/p>\n
\n if(root==null){
\n return;
\n }
\n postorder(root.left,list);
\n postorder(root.right,list);
\n list.add(root.val);
\n }
\n} <\/p>\n
\n\u8fed\u4ee3\u904d\u5386 <\/span><\/h2>\n<\/p>\n<\/p>\n
\n\u7edf\u4e00\u8fed\u4ee3<\/h2>\n<\/p>\n
\n\u5c42\u5e8f\u904d\u5386 <\/span><\/h2>\n<\/p>\n
\n https:\/\/programmercarl.com\/0102.%E4%BA%8C%E5%8F%89%E6%A0%91%E7%9A%84%E5%B1%82%E5%BA%8F%E9%81%8D%E5%8E%86.html<\/p>\n![\"\"](\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/01\/20260120054214-696f15b67e172.jpg\")
<\/p>\n
\n\u8f93\u51fa：[[3],[9,20],[15,7]]<\/p>\n
\n\u8f93\u51fa：[[1]]<\/p>\n
\n\u8f93\u51fa：[] <\/p>\n
\n * Definition for a binary tree node.
\n * public class TreeNode {
\n * int val;
\n * TreeNode left;
\n * TreeNode right;
\n * TreeNode() {}
\n * TreeNode(int val) { this.val = val; }
\n * TreeNode(int val, TreeNode left, TreeNode right) {
\n * this.val = val;
\n * this.left = left;
\n * this.right = right;
\n * }
\n * }
\n *\/
\nclass Solution {
\n List<List<Integer>> list=new ArrayList<List<Integer>>();<\/p>\n
\n if(root==null)return list;
\n Queue<TreeNode> queue=new LinkedList<TreeNode>();
\n queue.offer(root);
\n while(!queue.isEmpty()){
\n int size=queue.size();
\n List<Integer> templist=new ArrayList<Integer>();
\n while(size>0){
\n TreeNode node=queue.poll();
\n templist.add(node.val);
\n size–;
\n if(node.left!=null)queue.offer(node.left);
\n if(node.right!=null)queue.offer(node.right);
\n }
\n list.add(templist);
\n }
\n return list;
\n }
\n} <\/p>\n102.\u4e8c\u53c9\u6811\u7684\u5c42\u5e8f\u904d\u5386<\/h3>\n
\n
107.\u4e8c\u53c9\u6811\u7684\u5c42\u5e8f\u904d\u5386II<\/h3>\n
\n
![\"\"](\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/01\/20260120054214-696f15b695237.jpg\")
<\/p>\n
\n\u8f93\u51fa：[[15,7],[9,20],[3]]<\/p>\n
\n\u8f93\u51fa：[[1]]<\/p>\n
\n\u8f93\u51fa：[] <\/p>\n
\n * Definition for a binary tree node.
\n * public class TreeNode {
\n * int val;
\n * TreeNode left;
\n * TreeNode right;
\n * TreeNode() {}
\n * TreeNode(int val) { this.val = val; }
\n * TreeNode(int val, TreeNode left, TreeNode right) {
\n * this.val = val;
\n * this.left = left;
\n * this.right = right;
\n * }
\n * }
\n *\/
\nclass Solution {
\n List<List<Integer>> list=new LinkedList<List<Integer>>();
\n public List<List<Integer>> levelOrderBottom(TreeNode root) {
\n if(root==null)return list;
\n Queue<TreeNode> queue=new LinkedList<TreeNode>();
\n queue.offer(root);
\n while(!queue.isEmpty()){
\n int size=queue.size();
\n List<Integer> templist=new ArrayList<Integer>();
\n while(size>0){
\n TreeNode node=queue.poll();
\n templist.add(node.val);
\n size–;
\n if(node.left!=null)queue.offer(node.left);
\n if(node.right!=null)queue.offer(node.right);
\n }
\n list.addFirst(templist);
\n }
\n return list;
\n }
\n} <\/p>\n199.\u4e8c\u53c9\u6811\u7684\u53f3\u89c6\u56fe<\/h3>\n
\n
![\"\"](\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/01\/20260120054214-696f15b6a918a.png\")
<\/p>\n![\"\"](\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/01\/20260120054214-696f15b6c2ab0.png\")
<\/p>\n
\n * Definition for a binary tree node.
\n * public class TreeNode {
\n * int val;
\n * TreeNode left;
\n * TreeNode right;
\n * TreeNode() {}
\n * TreeNode(int val) { this.val = val; }
\n * TreeNode(int val, TreeNode left, TreeNode right) {
\n * this.val = val;
\n * this.left = left;
\n * this.right = right;
\n * }
\n * }
\n *\/
\nclass Solution {
\n List<Integer> list=new ArrayList<Integer>();
\n public List<Integer> rightSideView(TreeNode root) {
\n if(root==null)return list;
\n Queue<TreeNode> queue=new LinkedList<TreeNode>();
\n queue.offer(root);
\n while(!queue.isEmpty()){
\n int size=queue.size();
\n while(size>0){
\n TreeNode node=queue.poll();
\n if(size==1){
\n list.add(node.val);
\n }
\n size–;
\n if(node.left!=null)queue.offer(node.left);
\n if(node.right!=null)queue.offer(node.right);
\n }
\n }
\n return list;
\n }
\n} <\/p>\n637.\u4e8c\u53c9\u6811\u7684\u5c42\u5e73\u5747\u503c<\/h3>\n
\n
![\"\"](\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/01\/20260120054214-696f15b6e4329.jpg\")
<\/p>\n
\n\u8f93\u51fa：[3.00000,14.50000,11.00000]
\n\u89e3\u91ca：\u7b2c 0 \u5c42\u7684\u5e73\u5747\u503c\u4e3a 3,\u7b2c 1 \u5c42\u7684\u5e73\u5747\u503c\u4e3a 14.5,\u7b2c 2 \u5c42\u7684\u5e73\u5747\u503c\u4e3a 11 \u3002
\n\u56e0\u6b64\u8fd4\u56de [3, 14.5, 11] \u3002<\/p>\n![\"\"](\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/01\/20260120054215-696f15b701fb9.jpg\")
<\/p>\n
\n\u8f93\u51fa：[3.00000,14.50000,11.00000] <\/p>\n
\n * Definition for a binary tree node.
\n * public class TreeNode {
\n * int val;
\n * TreeNode left;
\n * TreeNode right;
\n * TreeNode() {}
\n * TreeNode(int val) { this.val = val; }
\n * TreeNode(int val, TreeNode left, TreeNode right) {
\n * this.val = val;
\n * this.left = left;
\n * this.right = right;
\n * }
\n * }
\n *\/
\nclass Solution {
\n List<Double> list =new ArrayList<Double>();
\n public List<Double> averageOfLevels(TreeNode root) {
\n if(root==null)return list;
\n Queue<TreeNode> queue=new LinkedList<TreeNode>();
\n queue.offer(root);
\n while(!queue.isEmpty()){
\n int size=queue.size();
\n int size1=queue.size();
\n double num=0.0;
\n while(size>0){
\n TreeNode node=queue.poll();
\n num+=node.val;
\n size–;
\n if(node.left!=null)queue.offer(node.left);
\n if(node.right!=null)queue.offer(node.right);
\n }
\n list.add(num\/size1);
\n }
\n return list;
\n }
\n} <\/p>\n429.N\u53c9\u6811\u7684\u5c42\u5e8f\u904d\u5386<\/h3>\n
\n
![\"\"](\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/01\/20260120054215-696f15b714142.png\")
<\/p>\n
\n\u8f93\u51fa：[[1],[3,2,4],[5,6]]<\/p>\n![\"\"](\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/01\/20260120054215-696f15b739273.png\")
<\/p>\n
\n\u8f93\u51fa：[[1],[2,3,4,5],[6,7,8,9,10],[11,12,13],[14]]<\/p>\n
\n\/\/ Definition for a Node.
\nclass Node {
\n public int val;
\n public List<Node> children;<\/p>\n
\n val = _val;
\n }<\/p>\n
\n val = _val;
\n children = _children;
\n }
\n};
\n*\/<\/p>\n
\n List<List<Integer>> list=new ArrayList<List<Integer>>();<\/p>\n
\n if(root==null)return list;
\n Queue<Node> queue=new LinkedList<Node>();
\n queue.offer(root);
\n while(!queue.isEmpty()){
\n int size=queue.size();
\n List<Integer> templist=new ArrayList<Integer>();
\n while(size>0){
\n Node node=queue.poll();
\n templist.add(node.val);
\n size–;
\n for(Node node1:node.children){
\n if(node1!=null)queue.offer(node1);
\n }
\n }
\n list.add(templist);
\n }
\n return list;
\n }
\n} <\/p>\n515.\u5728\u6bcf\u4e2a\u6811\u884c\u4e2d\u627e\u6700\u5927\u503c<\/h3>\n
\n
![\"\"](\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/01\/20260120054215-696f15b74e9e4.jpg\")
<\/p>\n
\n\u8f93\u51fa: [1,3,9]<\/p>\n
\n\u8f93\u51fa: [1,3] <\/p>\n
\n * Definition for a binary tree node.
\n * public class TreeNode {
\n * int val;
\n * TreeNode left;
\n * TreeNode right;
\n * TreeNode() {}
\n * TreeNode(int val) { this.val = val; }
\n * TreeNode(int val, TreeNode left, TreeNode right) {
\n * this.val = val;
\n * this.left = left;
\n * this.right = right;
\n * }
\n * }
\n *\/
\nclass Solution {
\n List<Integer> list=new ArrayList<Integer>();
\n public List<Integer> largestValues(TreeNode root) {
\n if(root==null)return list;
\n Queue<TreeNode> queue=new LinkedList<TreeNode>();
\n queue.offer(root);
\n while(!queue.isEmpty()){
\n int size=queue.size();
\n int max=Integer.MIN_VALUE;
\n while(size>0){
\n TreeNode node=queue.poll();
\n if(node.val>max)max=node.val;
\n size–;
\n if(node.left!=null)queue.offer(node.left);
\n if(node.right!=null)queue.offer(node.right);
\n }
\n list.add(max);
\n }
\n return list;
\n }
\n} <\/p>\n116.\u586b\u5145\u6bcf\u4e2a\u8282\u70b9\u7684\u4e0b\u4e00\u4e2a\u53f3\u4fa7\u8282\u70b9\u6307\u9488<\/h3>\n
\n
\n int val;
\n Node *left;
\n Node *right;
\n Node *next;
\n} <\/p>\n![\"\"](\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/01\/20260120054215-696f15b76111b.png\")
<\/p>\n
\n\u8f93\u51fa：[1,#,2,3,#,4,5,6,7,#]
\n\u89e3\u91ca：\u7ed9\u5b9a\u4e8c\u53c9\u6811\u5982\u56fe A \u6240\u793a，\u4f60\u7684\u51fd\u6570\u5e94\u8be5\u586b\u5145\u5b83\u7684\u6bcf\u4e2a next \u6307\u9488，\u4ee5\u6307\u5411\u5176\u4e0b\u4e00\u4e2a\u53f3\u4fa7\u8282\u70b9，\u5982\u56fe B \u6240\u793a\u3002\u5e8f\u5217\u5316\u7684\u8f93\u51fa\u6309\u5c42\u5e8f\u904d\u5386\u6392\u5217，\u540c\u4e00\u5c42\u8282\u70b9\u7531 next \u6307\u9488\u8fde\u63a5，'#' \u6807\u5fd7\u7740\u6bcf\u4e00\u5c42\u7684\u7ed3\u675f\u3002<\/p>\n
\n\u8f93\u51fa：[] <\/p>\n
\n\/\/ Definition for a Node.
\nclass Node {
\n public int val;
\n public Node left;
\n public Node right;
\n public Node next;<\/p>\n
\n val = _val;
\n }<\/p>\n
\n val = _val;
\n left = _left;
\n right = _right;
\n next = _next;
\n }
\n};
\n*\/<\/p>\n
\n public Node connect(Node root) {
\n if(root==null)return root;
\n Queue<Node> queue=new LinkedList<Node>();
\n queue.offer(root);
\n while(!queue.isEmpty()){
\n int size=queue.size();
\n while(size>0){
\n Node node=queue.poll();
\n if(size>1){
\n node.next=queue.peek();
\n }else{
\n node.next=null;
\n }
\n size–;
\n if(node.left!=null)queue.offer(node.left);
\n if(node.right!=null)queue.offer(node.right);
\n }
\n }
\n return root;
\n }
\n} <\/p>\n117.\u586b\u5145\u6bcf\u4e2a\u8282\u70b9\u7684\u4e0b\u4e00\u4e2a\u53f3\u4fa7\u8282\u70b9\u6307\u9488II<\/h3>\n
\n
\n int val;
\n Node *left;
\n Node *right;
\n Node *next;
\n} <\/p>\n![\"\"](\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/01\/20260120054215-696f15b793358.png\")
<\/p>\n
\n\u8f93\u51fa：[1,#,2,3,#,4,5,7,#]
\n\u89e3\u91ca：\u7ed9\u5b9a\u4e8c\u53c9\u6811\u5982\u56fe A \u6240\u793a，\u4f60\u7684\u51fd\u6570\u5e94\u8be5\u586b\u5145\u5b83\u7684\u6bcf\u4e2a next \u6307\u9488，\u4ee5\u6307\u5411\u5176\u4e0b\u4e00\u4e2a\u53f3\u4fa7\u8282\u70b9，\u5982\u56fe B \u6240\u793a\u3002\u5e8f\u5217\u5316\u8f93\u51fa\u6309\u5c42\u5e8f\u904d\u5386\u987a\u5e8f（\u7531 next \u6307\u9488\u8fde\u63a5），'#' \u8868\u793a\u6bcf\u5c42\u7684\u672b\u5c3e\u3002 <\/p>\n
\n\u8f93\u51fa：[] <\/p>\n
\n\/\/ Definition for a Node.
\nclass Node {
\n public int val;
\n public Node left;
\n public Node right;
\n public Node next;<\/p>\n
\n val = _val;
\n }<\/p>\n
\n val = _val;
\n left = _left;
\n right = _right;
\n next = _next;
\n }
\n};
\n*\/<\/p>\n
\n public Node connect(Node root) {
\n if(root==null)return root;
\n Queue<Node> queue=new LinkedList<Node>();
\n queue.offer(root);
\n while(!queue.isEmpty()){
\n int size=queue.size();
\n while(size>0){
\n Node node=queue.poll();
\n if(size>1){
\n node.next=queue.peek();
\n }else{
\n node.next=null;
\n }
\n size–;
\n if(node.left!=null)queue.offer(node.left);
\n if(node.right!=null)queue.offer(node.right);
\n }
\n }
\n return root;
\n }
\n} <\/p>\n104.\u4e8c\u53c9\u6811\u7684\u6700\u5927\u6df1\u5ea6<\/h3>\n
\n
![\"\"](\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/01\/20260120054215-696f15b7c6553.jpg\")
<\/p>\n<\/p>\n
\n\u8f93\u51fa：3<\/p>\n
\n\u8f93\u51fa：2
\n\/**
\n * Definition for a binary tree node.
\n * public class TreeNode {
\n * int val;
\n * TreeNode left;
\n * TreeNode right;
\n * TreeNode() {}
\n * TreeNode(int val) { this.val = val; }
\n * TreeNode(int val, TreeNode left, TreeNode right) {
\n * this.val = val;
\n * this.left = left;
\n * this.right = right;
\n * }
\n * }
\n *\/
\nclass Solution {
\n public int maxDepth(TreeNode root) {
\n int num=0;
\n if(root==null)return num;
\n Queue<TreeNode> queue=new LinkedList<TreeNode>();
\n queue.offer(root);
\n while(!queue.isEmpty()){
\n int size=queue.size();
\n while(size>0){
\n TreeNode node=queue.poll();
\n size–;
\n if(node.left!=null)queue.offer(node.left);
\n if(node.right!=null)queue.offer(node.right);
\n }
\n num++;
\n }
\n return num;
\n }
\n} <\/p>\n111.\u4e8c\u53c9\u6811\u7684\u6700\u5c0f\u6df1\u5ea6<\/h3>\n
\n
![\"\"](\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/01\/20260120054215-696f15b7d8a55.jpg\")
<\/p>\n
\n\u8f93\u51fa：2<\/p>\n
\n\u8f93\u51fa：5 <\/p>\n
\n * Definition for a binary tree node.
\n * public class TreeNode {
\n * int val;
\n * TreeNode left;
\n * TreeNode right;
\n * TreeNode() {}
\n * TreeNode(int val) { this.val = val; }
\n * TreeNode(int val, TreeNode left, TreeNode right) {
\n * this.val = val;
\n * this.left = left;
\n * this.right = right;
\n * }
\n * }
\n *\/
\nclass Solution {
\n public int minDepth(TreeNode root) {
\n int num=0;
\n if(root==null)return num;
\n Queue<TreeNode> queue=new LinkedList<TreeNode>();
\n queue.offer(root);
\n while(!queue.isEmpty()){
\n int size=queue.size();
\n while(size>0){
\n TreeNode node=queue.poll();
\n size–;
\n if(node.left!=null)queue.offer(node.left);
\n if(node.right!=null)queue.offer(node.right);
\n num++;
\n if(node.left==null&&node.right==null)return num;
\n }
\n }
\n return num;
\n }
\n} <\/p>\n
\n\u4e8c\u53c9\u6811\u7c7b\u578b
\n\u6ee1\u4e8c\u53c9\u6811
\n\u6ee1\u4e8c\u53c9\u6811：\u5982\u679c\u4e00\u68f5\u4e8c\u53c9\u6811\u53ea\u6709\u5ea6\u4e3a0\u7684\u7ed3\u70b9\u548c\u5ea6\u4e3a2\u7684\u7ed3\u70b9，\u5e76\u4e14\u5ea6\u4e3a0\u7684\u7ed3\u70b9\u5728\u540c\u4e00\u5c42\u4e0a，\u5219\u8fd9\u68f5\u4e8c\u53c9\u6811\u4e3a\u6ee1\u4e8c\u53c9\u6811\u3002
\n\u5982\u56fe\u6240\u793a： \u8fd9\u68f5\u4e8c\u53c9\u6811\u4e3a\u6ee1\u4e8c\u53c9\u6811，\u4e5f\u53ef\u4ee5\u8bf4\u6df1\u5ea6\u4e3ak，\u67092^k-1\u4e2a\u8282\u70b9\u7684\u4e8c\u53c9\u6811\u3002 \u5b8c\u5168\u4e8c\u53c9\u6811
\n\u4ec0\u4e48\u662f\u5b8c\u5168\u4e8c\u53c9\u6811？
\n\u5b8c\u5168\u4e8c\u53c9\u6811\u7684\u5b9a\u4e49\u5982\u4e0b：\u5728\u5b8c\u5168\u4e8c\u53c9\u6811\u4e2d，\u9664\u4e86\u6700\u5e95\u5c42\u8282\u70b9\u53ef\u80fd\u6ca1\u586b\u6ee1\u5916，<\/p>\n","protected":false},"author":2,"featured_media":62648,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[1813,427],"topic":[],"class_list":["post-62668","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-server","tag-1813","tag-427"],"yoast_head":"\n