LeetCode - Combination Sum II

22 Jan 2018 • LeetCode(Second)

Question Definition

Given a collection of candidate numbers (C) and a target number (T), find all unique combinations in C where the candidate numbers sums to T.

Each number in C may only be used once in the combination.

More …

LeetCode - Subsets II

21 Jan 2018 • LeetCode(Second)

Question Definition

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

Note: The solution set must not contain duplicate subsets.

For example, If nums = [1,2,2], a solution is:

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

My Java Solution

class Solution {
    public List<List<Integer>> subsetsWithDup(int[] nums) {
        Arrays.sort(nums);
        List<List<Integer>> result = new LinkedList<>();
        List<Integer> cur = new LinkedList<>();
        result.add(new LinkedList<>());

        for(int i = 1; i <= nums.length; i++){
            dfs(nums, 0, i, cur, result);
        }
        return result;
    }

    private void dfs(int[] nums, int start, int length, List<Integer> cur, List<List<Integer>> result){
        if(length == 0){
            result.add(new LinkedList<>(cur));
        }
        for(int i = start; i < nums.length; i++){
            if(i > start && nums[i] == nums[i - 1]) continue;
            cur.add(nums[i]);
            dfs(nums, i + 1, length - 1, cur, result);
            cur.remove(cur.size() - 1);
        }
    }
}