【LeetCode】112. Path Sum
阿新 • • 發佈:2018-12-15
Given a binary tree and a sum, determine if the tree has a root-to-leaf path such that adding up all the values along the path equals the given sum.
Note: A leaf is a node with no children.
Example:
Given the below binary tree and sum = 22
,
5 / \ 4 8 / / \ 11 13 4 / \ \ 7 2 1
return true, as there exist a root-to-leaf path 5->4->11->2
which sum is 22.
給一個二叉樹和一個值sum,判斷二叉樹是否有一條從根節點到葉子節點的路徑,使得路徑上節點值的和等於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==NULL) return false; if(root->left==NULL&&root->right==NULL){ if(sum==root->val) return true; else return false; } return hasPathSum(root->left,sum-root->val)||hasPathSum(root->right,sum-root->val); } };