LeetCde----40. 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.
• 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]]

Subscribe to see which companies asked this question

注意：有重复元素，会导致出现相同集合

public class Solution {        List<List<Integer>> result=new ArrayList<List<Integer>>();        public List<List<Integer>> combinationSum2(int[] candidates, int target) {        if(candidates.length<=0){return result;}        Arrays.sort(candidates);        helper(new ArrayList(),candidates,0,target);        return result;    }    public void helper(ArrayList<Integer> path,int [] candidates,int from,int target){        if(target==0){            List<Integer> list =new ArrayList<>(path);            result.add(list);        }else{            int weiyi=Integer.MAX_VALUE;;//防止重复            for(int i=from;i<candidates.length&&candidates[i]<=target;i++){                                if(candidates[i]!=weiyi){                path.add(candidates[i]);                helper(path,candidates,i+1,target-candidates[i]);                weiyi=candidates[i];                path.remove(path.size()-1);}                            }        }            }}