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 (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 2,3,6,7
and target 7
,
A solution set is:
[7]
[2, 2, 3]
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]
class Solution {
public:
vector<vector<int> > combinationSum(vector<int> &candidates, int target) {
sort(candidates.begin(), candidates.end());
vector<vector<int> > ret;
if (candidates.size() < 1) return ret;
vector<int> tmp;
combinationSum(ret, candidates, tmp, 0, target);
return ret;
}
void combinationSum(vector<vector<int> > &ret, vector<int> &candidates, vector<int> &tmp, int index, int target) {
if (target == 0) {
ret.push_back(tmp);
return;
}
if (target < 0) return;
for (int i = index; i < candidates.size(); i++) {
if (target >= candidates[i]) {
tmp.push_back(candidates[i]);
combinationSum(ret, candidates, tmp, i, target - candidates[i]);
tmp.pop_back();
}
}
}
};
class Solution {
public:
vector<vector<int> > combinationSum(vector<int> &candidates, int target) {
vector<vector<int> > ret;
vector<int> tmp;
sort(candidates.begin(),candidates.end());
combinationSumCore(ret,tmp,candidates,0,target);
return ret;
}
void combinationSumCore(vector<vector<int> > &ret,vector<int> &tmp,vector<int> &candidates,int index,int target) {
if(index == candidates.size() || target == 0) {
if(target == 0 && tmp.size() != 0) {
ret.push_back(tmp);
return;
}
return;
}
if(target-candidates[index] < 0) {
return;
}
tmp.push_back(candidates[index]);
combinationSumCore(ret,tmp,candidates,index,target-candidates[index]);
tmp.pop_back();
combinationSumCore(ret,tmp,candidates,index + 1,target);
}
};