【leetcode】90. subsets ii

1.题目描述

Given a collection of integers that might contain duplicates, nums, return all possible subsets (the power set).

给定一个可能包含重复元素的整数数组 nums,返回该数组所有可能的子集(幂集)。

Note: The solution set must not contain duplicate subsets.

说明:解集不能包含重复的子集。

Example:

Input: [1,2,2]
Output:
[
[2],
[1],
[1,2,2],
[2,2],
[1,2],
[]
]

2.Solutions

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public static List<List<Integer>> subsetsWithDup(int[] nums) {
List<List<Integer>> list = new ArrayList<>();
Arrays.sort(nums);
backtrack(list, new ArrayList<>(), nums, 0);
return list;
}

private static void (List<List<Integer>> list,
List<Integer> tempList, int [] nums, int start){
list.add(new ArrayList<>(tempList));
for(int i = start; i < nums.length; i++){
if(i > start && nums[i] == nums[i-1]) continue;
tempList.add(nums[i]);
backtrack(list, tempList, nums, i + 1);
tempList.remove(tempList.size() - 1);
}
}

参考:78. Subsets

(完)