Leetcode 113 Path Sum II

Given a binary tree and a sum, find all root-to-leaf paths where each path's sum equals the given sum.

For example:
Given the below binary tree and sum = 22,

              5             / \            4   8           /   / \          11  13  4         /  \    / \        7    2  5   1

return

[   [5,4,11,2],   [5,8,4,5]]

找出根到叶和为sum的路径，

在112题基础上多加一个记录路径和结果的变量就行了。

这一段树形的题刷得好无聊。

/** * 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:    void dfs(TreeNode* root,int now,int sum,vector<vector<int>>& res,vector<int> path)    {        now+=root->val;        path.push_back(root->val);        if(!root->left && !root->right)        {            if(now==sum) res.push_back(path);            return;        }        if(root->left) dfs(root->left,now,sum,res,path);        if(root->right) dfs(root->right,now,sum,res,path);    }    vector<vector<int>> pathSum(TreeNode* root, int sum) {        vector<vector<int>> res;        vector<int> path;        if(!root) return res;        dfs(root,0,sum,res,path);        return res;    }};