LeetCode 47. Permutations II(生成不同的组合-dfs)

Given a collection of numbers that might contain duplicates, return all possible unique permutations.

For example,
[1,1,2] have the following unique permutations:

[
  [1,1,2],
  [1,2,1],
  [2,1,1]
]

用的是dfs来完成

public class Solution {
    public List> permuteUnique(int[] nums) {
        if(nums==null||nums.length==0) return null;
		Arrays.sort(nums);           //把重复数字放在一起
        int len = nums.length;
        int[] isUsed = new int[len];
        List> result = new ArrayList>();
        ArrrayList store = new ArrayList();
        dfs(result,isUsed,store,nums);
        return result;
    }
    
    public void dfs(List> result, int[] isUsed, List store, int[] nums) {
    	if(store.size()==nums.length){
    		result.add(new ArrayList(store));
    		return;
    	}
    	for(int i=0;i0&&nums[i]==nums[i-1]&&isUsed[i-1]==0)  continue; //重复的当前面使用过才可以使用，前面未使用过直接使用会导致解重复
    		store.add(nums[i]);
    		isUsed[i]=1;
    		dfs(result,isUsed,store,nums);
    		isUsed[i]=0;
    		store.remove(store.size()-1);
    	}
	}
}

result.add(new ArrayList(store));

这个有问题等待补充！