题目描写叙述：
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.
bool Solution::hasPathSum(TreeNode *root, int sum)
{
if(root == NULL)
return false;
if(root->left == NULL && root->right == NULL)
return root->val - sum;
else
return hasPathSum(root->left,sum-root->val) || hasPathSum(root->right,sum-root->val);
}
本文转自mfrbuaa博客园博客，原文链接：http://www.cnblogs.com/mfrbuaa/p/5412727.html，如需转载请自行联系原作者
