Permutations II

Input: nums = [1,1,2]
Output:
[[1,1,2],
[1,2,1],
[2,1,1]]
Input: nums = [1,2,3]
Output: [[1,2,3],[1,3,2],[2,1,3],[2,3,1],[3,1,2],[3,2,1]]
  • 1 <= nums.length <= 8
  • -10 <= nums[i] <= 10

Solution :

public class Solution {
public IList<IList<int>> PermuteUnique(int[] nums)
{
IList<IList<int>> res = new List<IList<int>>();
bool[] used = new bool[nums.Length];
Permute(nums,0,nums.Length-1, res,used);
return res;
}

public static int[] swap(int[] nums , int i , int j)
{
int temp = 0;
temp = nums[i];
nums[i] = nums[j];
nums[j] = temp;
return nums;
}
public static void Permute(int[] nums,int left , int right, IList<IList<int>> res,bool[] used) {
if(left == right)
{
List<int> temp = nums.ToList();
if(!res.Contains(temp))
res.Add(temp);
}
else
{
HashSet<int> hset = new HashSet<int>();
for(int i = left ; i <= right ; i++)
{
if(hset.Contains(nums[i])){
continue;
}
hset.Add(nums[i]);
nums = swap(nums, left , i);
Permute(nums, left+1,right,res,used);
nums = swap(nums, left , i);
}
}
}
}

--

--

Get the Medium app

A button that says 'Download on the App Store', and if clicked it will lead you to the iOS App store
A button that says 'Get it on, Google Play', and if clicked it will lead you to the Google Play store