[LeetCode]经典 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 to T.

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, … , a_k) must be in non-descending order. (ie, a₁ ≤ a₂ ≤ … ≤ a_k).
• 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] 

根据Combination Sum做微小变动即可

public class Solution {public List<List<Integer>> combinationSum2(int[] candidates, int target) {List<List<Integer>> res = new ArrayList<>();List<Integer> list = new ArrayList<>();Arrays.sort(candidates);comSum(candidates, res, list, target, 0);return res;}private void comSum(int[] candidates, List<List<Integer>> res,List<Integer> list, int target, int start) {if (target == 0) {List<Integer> lis = new ArrayList<>(list);if(!res.contains(lis))  res.add(lis);return;}for (int i = start; i < candidates.length; i++) {if (target < candidates[i])return;list.add(candidates[i]);comSum(candidates, res, list, target - candidates[i], i+1);list.remove(Integer.valueOf(candidates[i]));}}}