2、问题分析 对于每个节点,如果其左子节点是叶子,则加上它的值,如果不是,递归,再对右子节点递归即可。 3、代码 1intsumOfLeftLeaves(TreeNode*root) {2if(root ==NULL)3return0;4intans =0;5if(root->left !=NULL) {6if(root->left->left == NULL && root->left->right ==NULL)7ans += roo...
LeetCode-404. Sum of Left Leaves Find the sum of all left leaves in a given binary tree. Example: 题目:将一棵树上所有的左叶子节点进行求和。 思路:关键在于找到终止条件,如果一棵树为空,返回0;如果左子树存在且为叶子结点,则将其值加入到sum中去,然后再递归去求左子树中左叶子节点之和和右子树...
Can you solve this real interview question? Sum of Left Leaves - Given the root of a binary tree, return the sum of all left leaves. A leaf is a node with no children. A left leaf is a leaf that is the left child of another node. Example 1: [https:
sum += sumOfLeftLeaves(root.left); } } sum += sumOfLeftLeaves(root.right);returnsum; } } AC:9 ms Python解法是这样的。 # Definition for a binary tree node.# class TreeNode:# def __init__(self, x):# self.val = x# self.left = None# self.right = NoneclassSolution:defsumOfL...
* TreeNode left; * TreeNode right; * TreeNode(int x) { val = x; } * } */ public class Solution { public int sumOfLeftLeaves(TreeNode head) { if (head == null) return 0; int left = 0, right = 0; if (head.left != null && head.left.left == null && head.left.right ...
左叶子之和(sum-of-left-leaves)(dfs)[简单] 链接https://leetcode-cn.com/problems/sum-of-left-leaves/ 耗时 解题:20 min 题解:6 min 题意 计算给定二叉树的所有左叶子之和。 思路 dfs 到的每个节点,都检查当前节点的左子节点是不是叶节点,如果是返回左节点的值,如果不是继续遍历左子树。无论是不...
Leetcode: Sum of Left Leaves,Recursion:是不是left子数完全由bottom往上第二层决定,如果是left子树且是叶子节点,那么就是leftleaves,parent得告诉child是不是在left子树BFS:
404. Sum of Left Leaves Easy Find the sum of all left leaves in a given binary tree. Example: 3 /\ 920 /\ 157 Thereare two left leavesinthe binary tree,withvalues9and15respectively.Return24. packageleetcode.easy; /** * Definition for a binary tree node. public class TreeNode { int...
of course we can modify the iterate version of preorder traverse, it’s very simple. but how are we gonna do it recursively? class Solution { private int sum = 0; public int sumOfLeftLeaves(TreeNode root) { if (root == null) return 0; ...
21 changes: 21 additions & 0 deletions 21 Solutions/404. Sum of Left Leaves.py Original file line numberDiff line numberDiff line change @@ -0,0 +1,21 @@ from typing import Optionalclass TreeNode: def __init__(self, val=0, left=None, right=None):...