LeetCode_path-sum

原题链接：https://leetcode.com/problems/path-sum/

/** * 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)            return false;        bool flag = false;        hasPathSum(root,sum,flag);        return flag;    }    void hasPathSum(TreeNode* root,int sum,bool &flag)    {        if(!root->left && !root->right)        {            if(sum == root->val)            {                flag = true;                return;            }            return;        }        sum -= root->val;        if(root->left)            hasPathSum(root->left,sum,flag);        if(root->right)            hasPathSum(root->right,sum,flag);    }};