112.路径总和

两天宇宙人

2020-02-20

😂自顶向下递归

class Solution {
public:
    bool hasPathSum(TreeNode* root, int sum) {
        s(root, 0, sum);
        return answer;
    }

    void s(TreeNode* root, int sum, int sum2) {
        if(!root)
            return ;
        int vl = sum + root->val;
        if(vl == sum2 && !root->left && !root->right) 
            answer = true;
        s(root->left, vl, sum2);
        s(root->right, vl, sum2);
    }
    bool answer = false;
};