Given a collection of candidate numbers (candidates) and a target number (target), find all unique combinations in candidates where the candidate numbers sums to target.
Each number in candidates may only be used once in the combination.
Note:
All numbers (including target) will be positive integers. The solution set must not contain duplicate combinations. Example 1:
Input: candidates = [10,1,2,7,6,1,5], target = 8, A solution set is: [ [1, 7], [1, 2, 5], [2, 6], [1, 1, 6] ] Example 2:
Input: candidates = [2,5,2,1,2], target = 5, A solution set is: [ [1,2,2], [5] ]
// 12ms, 83%
class Solution {
private:
vector<vector<int>> cmbSum(vector<int>& candidates, const vector<int>& stage, int start, int target) {
vector<vector<int>> res;
for (int i = start; i < candidates.size(); i++) {
if (i > start && candidates[i] == candidates[i-1])
continue;
auto val = candidates[i];
if (val > target) break;
if (val == target) {
res.push_back(stage);
res.back().push_back(val);
break;
}
auto stage2(stage);
stage2.push_back(val);
auto r = cmbSum(candidates, stage2, i+1, target - val);
if (!r.empty()) {
res.insert(res.end(), r.begin(), r.end());
}
}
return res;
}
public:
vector<vector<int>> combinationSum2(vector<int>& candidates, int target) {
sort(candidates.begin(), candidates.end());
vector<int> stage;
return cmbSum(candidates, stage, 0, target);
}
};