Combination Sum II Problem
Description
LeetCode Problem 40.
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:
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8
Input: candidates = [10,1,2,7,6,1,5], target = 8
Output:
[
[1,1,6],
[1,2,5],
[1,7],
[2,6]
]
Example 2:
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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
Sample C++ Code
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class Solution {
public:
vector<vector<int>> ans;
void dfs(vector<int>& candidates, vector<int>& comb, int target, int idx) {
if (target == 0)
ans.push_back(comb);
if (target <= 0)
return;
for (int i = idx; i < candidates.size(); i ++) {
if (i > idx && candidates[i] == candidates[i-1])
continue;
if (target >= candidates[i]) {
comb.push_back(candidates[i]);
dfs(candidates, comb, target-candidates[i], i+1);
comb.pop_back();
}
}
return;
}
vector<vector<int>> combinationSum2(vector<int>& candidates, int target) {
vector<int> comb;
sort(candidates.begin(), candidates.end());
dfs(candidates, comb, target, 0);
return ans;
}
};