Combination Sum II
Given a collection of candidate numbers (candidates) and a target number (target), find all unique combinations in candidates where the candidate numbers sum to target.
Each number in candidates may only be used once in the combination.
Note: The solution set must not contain duplicate combinations.
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Example 1:
Input: candidates = [10,1,2,7,6,1,5], target = 8
Output:
[
[1,1,6],
[1,2,5],
[1,7],
[2,6]
]
Example 2:
Input: candidates = [2,5,2,1,2], target = 5
Output:
[
[1,2,2],
[5]
]
solution
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class Solution {
private:
vector<vector<int>> ret;
public:
void dfs(vector<int>& candidates, int target, vector<int> current,
int begin) {
if (target < 0) {
return;
} else if (target == 0) {
ret.push_back(current);
return;
}
for (int i = begin; i < candidates.size(); i++) {
if (i > begin && candidates[i] == candidates[i - 1]) {
continue;
}
current.push_back(candidates[i]);
dfs(candidates, target - candidates[i], current, i + 1);
current.pop_back();
}
}
vector<vector<int>> combinationSum2(vector<int>& candidates, int target) {
int sum_of_elems = 0;
for (auto& n : candidates)
sum_of_elems += n;
if (sum_of_elems < target) {
return vector<vector<int>>();
}
vector<int> current;
sort(candidates.begin(), candidates.end());
dfs(candidates, target, current, 0);
return ret;
}
};
