Problem Description
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.
Solution
The solution is based on Combination Sum I
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class Solution {
List<List<Integer>> ans = new ArrayList<>();
public List<List<Integer>> combinationSum2(int[] candidates, int target) {
Arrays.sort(candidates);
find(candidates, 0, new ArrayList<>(), target);
return ans;
}
public void find(int[] arr, int i, List<Integer> list, int target){
if(target < 0) return;
if(i == arr.length){
if(target == 0){
ans.add(new ArrayList<Integer>(list));
}
return;
}
//Including
list.add(arr[i]);
find(arr, i+1, list, target-arr[i]);
list.remove(list.size()-1);
while(i<arr.length-1 && arr[i] == arr[i+1]) i++;
//Excluding
find(arr, i+1, list, target);
}
}