标签：leetcode   c++   tree   dfs   

欢迎大家阅读参考，如有错误或疑问请留言纠正，谢谢

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 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 Solution {
public:
    bool hasPathSum(TreeNode *root , int sum) {
        if(root==NULL)
			return false;
		PathSumUtil(root , sum , 0);
		return flag;
    }
private:
	bool flag = false;
    void PathSumUtil(TreeNode *root , int sum , int cur)
    {
		if( root->left==NULL && root->right==NULL )
		{
			if(cur + root->val ==sum)
				flag = true;
		}
		else
		{
			if( !flag && root->left!=NULL )
				PathSumUtil(root->left , sum , cur+root->val);
			if( !flag && root->right!=NULL )
				PathSumUtil(root->right , sum , cur+root->val);
		}
    }
};

leetcode_112_Path Sum

标签：leetcode   c++   tree   dfs   

原文地址：http://blog.csdn.net/keyyuanxin/article/details/43865839