Leetcode146: Path Sum II

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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]]

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

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