LeetCode Path Sum

链接: https://oj.leetcode.com/problems/path-sum/

深度优先搜索,.求出个从根到叶子节点的和..注意树中有负树

/**
 * Definition for binary tree
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution
{
	public:
		bool dfs(TreeNode *Node,int pathsum,int sum)
		{
		    
			if(Node!=NULL)
			{
				if(Node->left)
				    if(dfs(Node->left,pathsum+Node->left->val,sum))
				        return true;
				if(Node->right)
				    if(dfs(Node->right,pathsum+Node->right->val,sum))
				        return true;
				    
			}
			if(pathsum==sum&&Node->right==NULL&&Node->left==NULL)
				return true;
			return false;
		}
		bool hasPathSum(TreeNode *root,int sum )
		{
		    if(root==NULL)
		        return false;
			return dfs(root,0,sum-root->val);

		}
};