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.
class Solution {
public:
bool dfs(TreeNode* root,int sum ,int curSum)
{
if(root == NULL)
return false;
if(root->left == NULL&&root->right == NULL)
return root->val + curSum == sum;
return dfs(root->left,sum,curSum + root->val)||dfs(root->right,sum,curSum + root->val);
}
bool hasPathSum(TreeNode* root, int sum) {
return dfs(root,sum,0);
}
};
