《LeetCode力扣练习》代码随想录——二叉树（左叶子之和—Java）

---

---

刷题思路来源于 代码随想录

---

404. 左叶子之和

• 二叉树-后序遍历

  /*** Definition for a binary tree node.* public class TreeNode {* int val;* TreeNode left;* TreeNode right;* TreeNode() {}* TreeNode(int val) { this.val = val; }* TreeNode(int val, TreeNode left, TreeNode right) {* this.val = val;* this.left = left;* this.right = right;* }* }*/
  class Solution {public int sumOfLeftLeaves(TreeNode root) {return recursion(root);}private int recursion(TreeNode root) {if (root == null) {return 0;}if (root.left == null && root.right == null) {return 0;}int left;if (root.left != null && root.left.left == null && root.left.right == null) {left = root.left.val;} else {left = recursion(root.left);}int right = recursion(root.right);return left + right;}
  }
  

---