Day4

189. Rotate Array/189. Rotate Array.csproj

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+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net6.0</TargetFramework>
+    <RootNamespace>_189._Rotate_Array</RootNamespace>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

189. Rotate Array/Program.cs

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+namespace _189._Rotate_Array
+{
+    internal class Program
+    {
+        static void Main(string[] args)
+        {
+            var arr = new int[] { 1, 2, 3, 4, 5, 6};
+            new Solution().Rotate(arr, 3);
+            Console.WriteLine(String.Join(" ", arr));
+        }
+    }
+}

189. Rotate Array/Solution.cs

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+namespace _189._Rotate_Array;
+
+public class Solution
+{
+    public void Rotate(int[] nums, int k)
+    {
+        k %= nums.Length;
+        if (k == 0)
+            return;
+        int oneCycleLen = nums.Length/ GCD(nums.Length, k);
+        for (int i = 0; i < nums.Length / oneCycleLen; i++)
+            MoveTo(nums, nums[i], i + k, k, oneCycleLen);
+    }
+
+    private static void MoveTo(int[] array, int value, int to, int step, int curLen)
+    {
+        while (curLen-- > 0)
+        {
+            if (to >= array.Length)
+                to -= array.Length;
+            int buf = array[to];
+            array[to] = value;
+            to += step;
+            value = buf;
+        }
+    }
+
+    private static int GCD(int a, int b)
+    {
+        return b == 0 ? a : GCD(b, a % b);
+    }
+
+    
+}