LeetCode: Path Sum

Given a binary tree and a sum, determine if the tree has a root-to-leaf path such that adding up all the values along the path equals the given sum.

For example:
Given the below binary tree and sum = 22,

              5             / \            4   8           /   / \          11  13  4         /  \      \        7    2      1

return true, as there exist a root-to-leaf path 5->4->11->2 which sum is 22.

/** * Definition for a binary tree node. * struct TreeNode { *     int val; *     TreeNode *left; *     TreeNode *right; *     TreeNode(int x) : val(x), left(NULL), right(NULL) {} * }; */class Solution {public:    bool hasPathSum(TreeNode* root, int sum) {        if (root == NULL) return false;                queue<struct TreeNode*> Q;        Q.push(root);                while(!Q.empty()) {            struct TreeNode* tmp = Q.front();            if (tmp->left != NULL) {                tmp->left->val += tmp->val;                Q.push(tmp->left);            }                        if (tmp->right != NULL) {                tmp->right->val += tmp->val;                Q.push(tmp->right);            }                        if (tmp->left == NULL && tmp->right == NULL && tmp->val == sum) return true;                        Q.pop();        }                return false;            }};