LeetCode 112. 路径总和

LeetCode 112. 路径总和

思路：
dfs
代码：

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
 *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
 * };
 */
class Solution {
public:
    bool hasPathSum(TreeNode* root, int targetSum) {
        if(root) return dfs(root,targetSum);
        return false;
    }

    bool dfs(TreeNode* root,int targetSum){
        int tmp=root->val;
        targetSum-=root->val;

        if(!root->left && !root->right && !targetSum) return true;
        else{
            if(root->left){
                if(dfs(root->left,targetSum)) return true;
            }
            if(root->right){
                if(dfs(root->right,targetSum)) return true;
            }
        } 
        targetSum+=tmp;
        return false;
    }
};