From 8804cec9574badcdc1e690c6db1314a463c10458 Mon Sep 17 00:00:00 2001
From: Sarthak Chaudhary <86872379+SarthakChaudhary46@users.noreply.github.com>
Date: Sat, 13 Jan 2024 13:59:30 +0530
Subject: [PATCH] Feature/4638 array right rotation (#5014)

* Create ArrayRightRotationTest.java

* Create ArrayRightRotation.java

* The updated one

* The updated one

* Added the test cases

* Added new test cases!

* Update ArrayRightRotation.java

* Update ArrayRightRotationTest.java
---
 .../others/ArrayRightRotation.java            | 28 ++++++++++
 .../others/ArrayRightRotationTest.java        | 53 +++++++++++++++++++
 2 files changed, 81 insertions(+)
 create mode 100644 src/test/java/com/thealgorithms/others/ArrayRightRotation.java
 create mode 100644 src/test/java/com/thealgorithms/others/ArrayRightRotationTest.java

diff --git a/src/test/java/com/thealgorithms/others/ArrayRightRotation.java b/src/test/java/com/thealgorithms/others/ArrayRightRotation.java
new file mode 100644
index 000000000..a78ef81f3
--- /dev/null
+++ b/src/test/java/com/thealgorithms/others/ArrayRightRotation.java
@@ -0,0 +1,28 @@
+package com.thealgorithms.others;
+
+public class ArrayRightRotation {
+    public static int[] rotateRight(int[] arr, int k) {
+        if (arr == null || arr.length == 0 || k < 0) {
+            throw new IllegalArgumentException("Invalid input");
+        }
+
+        int n = arr.length;
+        k = k % n; // Handle cases where k is larger than the array length
+
+        reverseArray(arr, 0, n - 1);
+        reverseArray(arr, 0, k - 1);
+        reverseArray(arr, k, n - 1);
+
+        return arr;
+    }
+
+    private static void reverseArray(int[] arr, int start, int end) {
+        while (start < end) {
+            int temp = arr[start];
+            arr[start] = arr[end];
+            arr[end] = temp;
+            start++;
+            end--;
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/others/ArrayRightRotationTest.java b/src/test/java/com/thealgorithms/others/ArrayRightRotationTest.java
new file mode 100644
index 000000000..f132d56dd
--- /dev/null
+++ b/src/test/java/com/thealgorithms/others/ArrayRightRotationTest.java
@@ -0,0 +1,53 @@
+package com.thealgorithms.others;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+
+import org.junit.jupiter.api.Test;
+
+class ArrayRightRotationTest {
+
+    @Test
+    void testArrayRightRotation() {
+        int[] arr = {1, 2, 3, 4, 5, 6, 7};
+        int k = 3;
+        int[] expected = {5, 6, 7, 1, 2, 3, 4};
+        int[] result = ArrayRightRotation.rotateRight(arr, k);
+        assertArrayEquals(expected, result);
+    }
+
+    @Test
+    void testArrayRightRotationWithZeroSteps() {
+        int[] arr = {1, 2, 3, 4, 5, 6, 7};
+        int k = 0;
+        int[] expected = {1, 2, 3, 4, 5, 6, 7};
+        int[] result = ArrayRightRotation.rotateRight(arr, k);
+        assertArrayEquals(expected, result);
+    }
+
+    @Test
+    void testArrayRightRotationWithEqualSizeSteps() {
+        int[] arr = {1, 2, 3, 4, 5, 6, 7};
+        int k = arr.length;
+        int[] expected = {1, 2, 3, 4, 5, 6, 7};
+        int[] result = ArrayRightRotation.rotateRight(arr, k);
+        assertArrayEquals(expected, result);
+    }
+
+    @Test
+    void testArrayRightRotationWithLowerSizeSteps() {
+        int[] arr = {1, 2, 3, 4, 5, 6, 7};
+        int k = 2;
+        int[] expected = {6, 7, 1, 2, 3, 4, 5};
+        int[] result = ArrayRightRotation.rotateRight(arr, k);
+        assertArrayEquals(expected, result);
+    }
+
+    @Test
+    void testArrayRightRotationWithHigherSizeSteps() {
+        int[] arr = {1, 2, 3, 4, 5, 6, 7};
+        int k = 10;
+        int[] expected = {5, 6, 7, 1, 2, 3, 4};
+        int[] result = ArrayRightRotation.rotateRight(arr, k);
+        assertArrayEquals(expected, result);
+    }
+}