[csharp] 46. Permutations

csharp/46-Permutations.cs

@@ -0,0 +1,26 @@
+public class Solution
+{
+ public IList<IList<int>> Permute(int[] nums)
+ {
+ var result = new List<IList<int>>();
+ PermuteRecurse(result, nums, 0);
+ return result;
+ }
+
+ private void PermuteRecurse(List<IList<int>> res, int[] arr, int start)
+ {
+ if (start == arr.Length)
+ {
+ var list = arr.Select(t => (t)).ToList();
+ res.Add(list);
+ return;
+ }
+
+ for (var i = start; i < arr.Length; i++)
+ {
+ (arr[start], arr[i]) = (arr[i], arr[start]);
+ PermuteRecurse(res, arr, start + 1);
+ (arr[start], arr[i]) = (arr[i], arr[start]);
+ }
+ }
+}