LeetCode Combination Sum II

Given a collection of candidate numbers (C) and a target number (T), find all unique combinations in C where the candidate numbers sums toT.

Each number in C may only be used once in the combination.

Note:

• All numbers (including target) will be positive integers.
• Elements in a combination (a1, a2, … , ak) must be in non-descending order. (ie, a1 ≤ a2 ≤ … ≤ ak).
• The solution set must not contain duplicate combinations.

 

For example, given candidate set 10,1,2,7,6,1,5 and target 8, 
A solution set is: 
[1, 7] 
[1, 2, 5] 
[2, 6] 
[1, 1, 6] 

 

public class Solution {
    List<List<Integer>> result;
    public List<List<Integer>> combinationSum2(int[] num, int target) {
        result = new ArrayList<List<Integer>>();
        List<Integer> list = new ArrayList<Integer>();
        Arrays.sort(num);
        combination(num, 0, list, target);
        return result;
    }
    
        void combination(int[] num,int index,List<Integer> curr,int target) {
        if (target == 0) {
            result.add(new ArrayList<Integer>(curr));

        } else {
            for (int i = index; i < num.length; i++) {
                if (i != index && num[i] == num[i - 1]) {
                    continue;
                }
                if (target >= num[i]) {
                    curr.add(num[i]);
                    combination(num, i + 1, curr, target - num[i]);
                    curr.remove(curr.size() - 1);
                }
            }
        }

    }
    
}