[LeetCode] Path Sum II 深度搜索

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]
]

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　　　这题其实就是深度搜索，代码：

#include <vector>
#include <iostream>
using namespace std;
/**
* Definition for binary tree
*/
struct TreeNode {
int val;
TreeNode *left;
TreeNode *right;
TreeNode(int x) : val(x), left(NULL), right(NULL) {}
};

class Solution {
public:
vector<vector<int> > ret;
vector<int> nowPath;
vector<vector<int> > pathSum(TreeNode *root, int sum) {
ret.clear();
nowPath.clear();
if(root==NULL)  return ret;
help_f(root,sum);
return ret;
}

void help_f(TreeNode *root,int sum)
{
if(root==NULL)  return ;
nowPath.push_back(root->val);
help_f(root->left,sum - root->val);
help_f(root->right,sum - root->val);
if(root->left==NULL&&root->right==NULL&&sum==root->val)
ret.push_back(nowPath);
nowPath.pop_back();
}
};

int main()
{
return 0;
}

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