# 题目：

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

The same repeated number may be chosen from C unlimited number of times.

Note:

• All numbers (including target) will be positive integers.
• Elements in a combination (a1a2, … , ak) must be in non-descending order. (ie, a1 ≤ a2 ≤ … ≤ ak).
• The solution set must not contain duplicate combinations.

For example, given candidate set `2,3,6,7` and target `7`
A solution set is:
`[7]`
`[2, 2, 3]`

# 代码：

``````class Solution {
public:
vector<vector<int> > result;
vector<int> candidates;
vector<vector<int> > combinationSum(vector<int> &candidates, int target) {
this->candidates = candidates;
sort(this->candidates.begin(),this->candidates.end());
getCombination(*(new vector<int>()),0,target);
return result;
}

void getCombination(vector<int> v, int sum, int target)
{

int last=INT_MIN;
if(v.size()>0)
{
last = v[v.size()-1];
}
int i = 0;
for(;i<candidates.size();i++)
{
if(candidates[i]>=last)
{
break;
}
}
for(int j=i;j<candidates.size();j++)
{
if(sum + candidates[j]==target)
{
v.push_back(candidates[j]);
result.push_back(v);
v.pop_back();
}
else if(sum + candidates[j]<target)
{
v.push_back(candidates[j]);
getCombination(v, sum+candidates[j],target);
v.pop_back();
}
else
{
return;
}
}
}
};``````
原文作者：Allanxl
原文地址: https://blog.csdn.net/lanxu_yy/article/details/17594497
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