Sum Of Left Leaves Problem
Description
LeetCode Problem 404.
Given the root of a binary tree, return the sum of all left leaves.
Example 1:
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Input: root = [3,9,20,null,null,15,7]
Output: 24
Explanation: There are two left leaves in the binary tree, with values 9 and 15 respectively.
Example 2:
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Input: root = [1]
Output: 0
Constraints:
- The number of nodes in the tree is in the range [1, 1000].
- -1000 <= Node.val <= 1000
Sample C++ Code
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/**
* Definition for a binary tree node.
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode() : val(0), left(nullptr), right(nullptr) {}
* TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
* TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
* };
*/
class Solution {
public:
int sumOfLeftLeaves(TreeNode* root) {
if (root == NULL)
return 0;
if (root->left == NULL)
return sumOfLeftLeaves(root->right);
if (root->left->left == NULL && root->left->right == NULL)
return root->left->val + sumOfLeftLeaves(root->right);
return sumOfLeftLeaves(root->left) + sumOfLeftLeaves(root->right);
}
};