给定一个可包含重复数字的序列,返回所有不重复的全排列。示例:
输入: [1,1,2]
输出:
[
[1,1,2],
[1,2,1],
[2,1,1]
]与上道题的区别是有重复的数,结果里很容易重复
private List<List<Integer>> ret=new ArrayList(); public List<List<Integer>> permuteUnique(int[] nums) { helper(Arrays.stream(nums).boxed().sorted().collect(Collectors.toList()),new ArrayList()); return ret;}public void helper(List<Integer> remain,List<Integer> list){ if(remain.size()==0){ ret.add(new ArrayList(list)); return; } for(int i=0;i<remain.size();i++){ if(i>0 && remain.get(i)==remain.get(i-1)) continue; int value=remain.get(i); remain.remove(i); list.add(value); helper(remain,list); remain.add(i,value); list.remove(list.size()-1); }}
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