[LeetCode]problem 216. Combination Sum III

TAG

方法

set

代码

class Solution {
public:
vector<vector<int>> combinationSum3(int k, int n) {
vector<vector<int>> result ;
vector<int> selectedNums;
selectNum(k, selectedNums, n, result);
return result;
}
private:
void selectNum(int k,
vector<int> ¤tSelectedNums,
int target,
vector<vector<int>> &result,
size_t startPos=1)
{
if(currentSelectedNums.size() > k){ return ;}
if(target < 0) { return ;}
else if(target == 0)
{
if(currentSelectedNums.size() == k) {result.push_back(currentSelectedNums);}
return;
}
for(int i = startPos; i <= 9 && i <= target; ++i)
{
// try to add current number to currentSelectedNums
currentSelectedNums.push_back(i);
selectNum(k, currentSelectedNums, target - i, result, i+1);
// try next num
currentSelectedNums.pop_back();
}

}
};