LeetCode 112. Path Sum(判断路径和是否等于一个数)
题意:判断路径和是否等于一个数。
分析:递归判断左右子树是否有和为sum-(root->val)的路径即可。
/** * 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 == NULL) return false; if(root -> left == NULL && root -> right == NULL && root -> val == sum) return true; return hasPathSum(root -> left, sum - root -> val) || hasPathSum(root -> right, sum - root -> val); } };