代码随想录——子集Ⅱ（Leecode 90）

题目链接

回溯

class Solution {List<List<Integer>> res = new ArrayList<List<Integer>>();List<Integer> list = new ArrayList<Integer>();boolean[] used; public List<List<Integer>> subsetsWithDup(int[] nums) {used = new boolean[nums.length];Arrays.fill(used, false);Arrays.sort(nums);backtracking(nums, 0);return res;}public void backtracking(int[] nums, int startIndex){// 求全部子集res.add(new ArrayList<>(list));for(int i = startIndex; i < nums.length; i++){// 去重if(i > 0 && nums[i] == nums[i - 1] && used[i - 1] == false){continue;}used[i] = true;list.add(nums[i]);backtracking(nums, i + 1);used[i] = false;list.removeLast();}}
}

本题是子集问题+组合求和Ⅲ的综合