LeetCode 112. Path Sum

代码：

class Solution {public:    bool hasPathSum(TreeNode *root, int sum)     {    if (root!=NULL && root->left==NULL && root->right==NULL && root->val==sum)    {    return true;    } else if (root!=NULL)    {    return hasPathSum(root->left, sum-root->val)    || hasPathSum(root->right, sum-root->val);    } else    {    return false;    }    }};