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]
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&&i<S.size()-1)
findSum(S,sum+S[i],i+1,t,buf,res);
buf.pop_back();
while(i<S.size()-1&&S[i]==S[i+1])
i++;
}
}
vector<vector<int> > combinationSum2(vector<int> &num, int
target) {
vector<int> buf;
vector<vector<int>> res;
sort(num.begin(),num.end());
findSum(num,0,0,target,buf,res);
return
res;
}
}; |