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: 5
/ 4 8
/ / 11 13 4
/ \ 7 2 1
return true, as there exist a root-to-leaf path5->4->11->2which sum is 22.
/**
* Definition for binary tree
* 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;
if(root->left==NULL &&root->right==NULL && sum-root->val==0) return true;
return hasPathSum(root->left,sum-root->val) || hasPathSum(root->right,sum-root->val);
}
};
原文：http://www.cnblogs.com/dd2hm/p/7507144.html