LeetCode 题解（29）: Path Sum II

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题目：

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]]

题解：

递归。

class Solution {public:    vector<vector<int> > pathSum(TreeNode *root, int sum) {        vector<vector<int>> result;        vector<int> temp;        pathSumRecursion(result, root, sum, temp);        return result;    }        void pathSumRecursion(vector<vector<int>> & result, TreeNode *root, int sum, vector<int> & temp)    {        if(!root){            temp.push_back(0);return;}        if(root->val == sum && !root->left && !root->right)        {            temp.push_back(root->val);            result.push_back(temp);            return;        }        else if(!root->left && !root->right)        {            temp.push_back(root->val);            return;        }                temp.push_back(root->val);        pathSumRecursion( result, root->left, sum - root->val, temp);        temp.pop_back();        pathSumRecursion( result, root->right, sum - root->val, temp);        temp.pop_back();    }};

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