LeetCode *** 40. Combination Sum II

题目：

Given a collection of candidate numbers (C) and a target number (T), find all unique combinations in
C where the candidate numbers sums to T.

Each number in C may only be used once in the combination.

Note:

All numbers (including target) will be positive integers.
Elements in a combination (a1,
a2, … , ak) must be in non-descending order. (ie,
a1 ≤ a2 ≤ … ≤
ak).
The solution set must not contain duplicate combinations.

For example, given candidate set

10,1,2,7,6,1,5

and target

8

,

A solution set is:

[1, 7]

[1, 2, 5]

[2, 6]

[1, 1, 6]

分析：

每次写完代码都不敢看结果。。

代码：

class Solution {
public:
int tg;
vector<vector<int>> res;
vector<vector<int>> combinationSum2(vector<int>& candidates, int target) {
sort(candidates.begin(),candidates.end());
tg=target;
vector<int>tmp;
dfs(candidates,tmp,0,0);
return res;
}
void dfs(vector<int>& nums,vector<int> tmp,int start,int sum){
int s,i=start;
while(i<nums.size()){
while(i!=start&&nums[i]==nums[i-1])i++;
s=sum+nums[i];
if(s==tg){
tmp.push_back(nums[i]);
res.push_back(tmp);
return;
}
if(s<tg){
tmp.push_back(nums[i]);
dfs(nums,tmp,i+1,s);
tmp.pop_back();
}
i++;
}
}
};