LeetCode.501.二叉搜索树中的众数

501. 二叉搜索树中的众数

难度&＃xff1a;easy

一道很考细节的简单题

/*** Definition for a binary tree node.* public class TreeNode {* int val;* TreeNode left;* TreeNode right;* TreeNode() {}* TreeNode(int val) { this.val &＃61; val; }* TreeNode(int val, TreeNode left, TreeNode right) {* this.val &＃61; val;* this.left &＃61; left;* this.right &＃61; right;* }* }*/
class Solution {public int[] findMode(TreeNode root) {Stack stack &＃61; new Stack<>();List list &＃61; new ArrayList<>();TreeNode pre &＃61; null;TreeNode cur &＃61; root;int count &＃61; 0;int maxCount &＃61; 0;while (cur !&＃61; null || !stack.isEmpty()) {if (cur !&＃61; null) {stack.push(cur);cur &＃61; cur.left;} else {cur &＃61; stack.pop();if (pre &＃61;&＃61; null || pre.val !&＃61; cur.val) {count &＃61; 1;} else if (pre.val &＃61;&＃61; cur.val){count&＃43;&＃43;;} if (count > maxCount) {maxCount &＃61; count;// count &＃61; 0;list.clear();list.add(cur.val);} else if (count &＃61;&＃61; maxCount) {list.add(cur.val);}pre &＃61; cur;cur &＃61; cur.right;}}int[] ans &＃61; new int[list.size()];for (int i &＃61; 0; i }