Permutations

Input: nums = [1,2,3]
Output: [[1,2,3],[1,3,2],[2,1,3],[2,3,1],[3,1,2],[3,2,1]]
Input: nums = [0,1]
Output: [[0,1],[1,0]]
Input: nums = [1]
Output: [[1]]
  • 1 <= nums.length <= 6
  • -10 <= nums[i] <= 10
  • All the integers of nums are unique.
public class Solution {
public IList<IList<int>> Permute(int[] nums) {
IList<IList<int>> res = new List<IList<int>>();
Permute(nums,0,nums.Length-1, res);
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) {
if(left == right)
{
List<int> temp = nums.ToList();
res.Add(temp);
}
else
{
for(int i = left ; i <= right ; i++)
{
nums = swap(nums, left , i);
Permute(nums, left+1,right,res);
nums = swap(nums, left , i);
}
}
}

}

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