leetcode 40 - Combination Sum II

https://leetcode.com/problems/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.

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]
]

Constraints:

1 <= candidates.length <= 100
1 <= candidates[i] <= 50
1 <= target <= 30

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class Solution {
public:
vector<vector<int>> all_result;

vector<vector<int>> combinationSum2(vector<int>& candidates, int target) {
vector<int> result;

sort(candidates.begin(), candidates.end());
combinationSum2(candidates, target, 0, result);
return all_result;
}

void combinationSum2(vector<int>& candidates, int target, int i, vector<int> &result) {
int size = candidates.size();

if (target <= 0 || i == size) {
if (target == 0)
all_result.push_back(result);
return;
}

for (int j = i; j < size; j++) {
if (j > i && candidates[j] == candidates[j - 1])
continue;

result.push_back(candidates[j]);
combinationSum2(candidates, target - candidates[j], j + 1, result);
result.pop_back();
}
}
};