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]
Code:
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class
Solution {
public:
void
findSum(vector<int> &S,int
sum,int
level,int
&t,vector<int> &buf,vector<vector<int>> &res){
for(int
i=level;i<S.size();i++){
buf.push_back(S[i]);
if(sum+S[i]==t)
res.push_back(buf);
if(sum+S[i]<=t)
findSum(S,sum+S[i],i,t,buf,res);
buf.pop_back();
}
}
vector<vector<int> > combinationSum(vector<int> &candidates, int
target) {
vector<int> buf;
vector<vector<int>> res;
sort(candidates.begin(),candidates.end());
findSum(candidates,0,0,target,buf,res);
return
res;
}
}; |