leetcode(90)子集 2

子集2

class Solution {
    public List<List<Integer>> subsetsWithDup(int[] nums) {
        Arrays.sort(nums);
        int len = nums.length;
        List<List<Integer>> result = new ArrayList<List<Integer>>();
        int[] index = new int[len];
        index[0] = 1;
        for(int i=1;i<len;++i) {
            if(nums[i]==nums[i-1]) {
                index[i] = index[i-1]+1;
            }else {
                index[i] = 1;
            }
        }
        subsetsWithDup2(nums,len,result,index);
        return result;
    }
    public void subsetsWithDup2(int[] nums, int len, List<List<Integer>> result, int[] index) {
        if(len == 0) {
            List<Integer> element = new ArrayList<>();
            result.add(element);
        }else {
            subsetsWithDup2(nums, len - index[len-1], result,index);
            int size = result.size();
            for(int i=0;i<size;++i) {
                List<Integer> tempElement = result.get(i);
                for(int j=0;j<index[len-1];++j) {
                    tempElement = (List)((ArrayList)tempElement).clone();
                    tempElement.add(nums[len-1]);
                    result.add(tempElement);
                }
            }
        }
    }
}