path sum 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. For example : Given the below the 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. class Solution1{ /* Definition for binary tree struct TreeNode{ int val; TreeNode *left; TreeNode *right; TreeNode(int x):val(x),left(NULL),right(NULL){} }; */ 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); } };
怕什么真理无穷,进一寸有一寸的欢喜。---胡适