From 219fbd38f625f02f87f66ac6bf88460d5b27195e Mon Sep 17 00:00:00 2001
From: Nikita Rusetskii <rusetscky@outlook.com>
Date: Thu, 4 Jul 2024 19:04:56 +0200
Subject: [PATCH 1/2] Add Reverse String Problem

---
 .../java/com/xtenzq/arrays/TwoPointers.java   | 18 +++++++
 .../com/xtenzq/arrays/TwoPointersTest.java    | 49 +++++++++++++++++++
 2 files changed, 67 insertions(+)

diff --git a/algorithms-and-data-structures/src/main/java/com/xtenzq/arrays/TwoPointers.java b/algorithms-and-data-structures/src/main/java/com/xtenzq/arrays/TwoPointers.java
index 686b365..038f33c 100644
--- a/algorithms-and-data-structures/src/main/java/com/xtenzq/arrays/TwoPointers.java
+++ b/algorithms-and-data-structures/src/main/java/com/xtenzq/arrays/TwoPointers.java
@@ -110,5 +110,23 @@ public static boolean isSubsequence(String s, String t) {
 
         return i == s.length();
     }
+
+    /**
+     * Reverses the input array of characters in-place.
+     *
+     * @param s the array of characters to be reversed
+     * @implNote This method runs in {@code O(n)} time complexity and {@code O(1)} space complexity,
+     * where {@code n} is the length of {@code s}.
+     */
+    public static void reverseString(char[] s) {
+        int i = 0, j = s.length - 1;
+        while (i < j) {
+            var temp = s[i];
+            s[i] = s[j];
+            s[j] = temp;
+            i++;
+            j--;
+        }
+    }
 }
 
diff --git a/algorithms-and-data-structures/src/test/java/com/xtenzq/arrays/TwoPointersTest.java b/algorithms-and-data-structures/src/test/java/com/xtenzq/arrays/TwoPointersTest.java
index 192970a..613d9de 100644
--- a/algorithms-and-data-structures/src/test/java/com/xtenzq/arrays/TwoPointersTest.java
+++ b/algorithms-and-data-structures/src/test/java/com/xtenzq/arrays/TwoPointersTest.java
@@ -6,6 +6,7 @@
 import static com.xtenzq.arrays.TwoPointers.canBeSummed;
 import static com.xtenzq.arrays.TwoPointers.isPalindrome;
 import static com.xtenzq.arrays.TwoPointers.mergeSortedArrays;
+import static com.xtenzq.arrays.TwoPointers.reverseString;
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
@@ -281,4 +282,52 @@ void testInterleavedNonSubsequence() {
         String t = "abcde";
         assertFalse(isSubsequence(s, t));
     }
+
+    @Test
+    void testReverseStringWithEvenNumberOfCharacters() {
+        char[] input = {'h', 'e', 'l', 'l', 'o'};
+        char[] expected = {'o', 'l', 'l', 'e', 'h'};
+        reverseString(input);
+        assertArrayEquals(expected, input);
+    }
+
+    @Test
+    void testReverseStringWithOddNumberOfCharacters() {
+        char[] input = {'a', 'b', 'c', 'd', 'e'};
+        char[] expected = {'e', 'd', 'c', 'b', 'a'};
+        reverseString(input);
+        assertArrayEquals(expected, input);
+    }
+
+    @Test
+    void testReverseStringWithSingleCharacter() {
+        char[] input = {'a'};
+        char[] expected = {'a'};
+        reverseString(input);
+        assertArrayEquals(expected, input);
+    }
+
+    @Test
+    void testReverseStringWithEmptyArray() {
+        char[] input = {};
+        char[] expected = {};
+        reverseString(input);
+        assertArrayEquals(expected, input);
+    }
+
+    @Test
+    void testReverseStringWithRepeatedCharacters() {
+        char[] input = {'a', 'a', 'a', 'a'};
+        char[] expected = {'a', 'a', 'a', 'a'};
+        reverseString(input);
+        assertArrayEquals(expected, input);
+    }
+
+    @Test
+    void testReverseStringWithSpecialCharacters() {
+        char[] input = {'!', '@', '#', '$', '%'};
+        char[] expected = {'%', '$', '#', '@', '!'};
+        reverseString(input);
+        assertArrayEquals(expected, input);
+    }
 }
\ No newline at end of file

From ac28f08f5c241b295109290403cf6356cc5f1640 Mon Sep 17 00:00:00 2001
From: Nikita Rusetskii <rusetscky@outlook.com>
Date: Thu, 4 Jul 2024 19:10:58 +0200
Subject: [PATCH 2/2] Add link to LeetCode problem

---
 .../src/main/java/com/xtenzq/arrays/TwoPointers.java             | 1 +
 1 file changed, 1 insertion(+)

diff --git a/algorithms-and-data-structures/src/main/java/com/xtenzq/arrays/TwoPointers.java b/algorithms-and-data-structures/src/main/java/com/xtenzq/arrays/TwoPointers.java
index 038f33c..3bb5098 100644
--- a/algorithms-and-data-structures/src/main/java/com/xtenzq/arrays/TwoPointers.java
+++ b/algorithms-and-data-structures/src/main/java/com/xtenzq/arrays/TwoPointers.java
@@ -117,6 +117,7 @@ public static boolean isSubsequence(String s, String t) {
      * @param s the array of characters to be reversed
      * @implNote This method runs in {@code O(n)} time complexity and {@code O(1)} space complexity,
      * where {@code n} is the length of {@code s}.
+     * @see <a href="https://leetcode.com/problems/reverse-string/">344. Reverse String</a>
      */
     public static void reverseString(char[] s) {
         int i = 0, j = s.length - 1;