Add RockPaperScissors game implementation

src/main/java/com/thealgorithms/puzzlesandgames/RockPaperScissors.java

@@ -0,0 +1,41 @@
+package com.thealgorithms.puzzlesandgames;
+
+import java.util.Random;
+import java.util.Scanner;
+
+/**
+ * <a href="https://en.wikipedia.org/wiki/Rock_paper_scissors"></a>
+ * RockPaperScissors (Jokenpô)
+ * Simple terminal game where the user plays Rock, Paper, Scissors against the computer.
+ * Rules:
+ * - Rock beats Scissors
+ * - Scissors beats Paper
+ * - Paper beats Rock
+ * Example:
+ * User: rock
+ * Computer: scissors
+ * Result: You win!
+ * Author: Lígia Alves (Hacktoberfest 2025)
+ */
+public final class RockPaperScissors {
+
+    private RockPaperScissors() {
+        throw new UnsupportedOperationException("Utility class");
+    }
+
+    public static String getResult(String userChoice, String computerChoice) {
+        if (userChoice.equals(computerChoice)) {
+            return "It's a tie!";
+        } else if ((userChoice.equals("rock") && computerChoice.equals("scissors")) || (userChoice.equals("scissors") && computerChoice.equals("paper")) || (userChoice.equals("paper") && computerChoice.equals("rock"))) {
+            return "You win! :D ";
+        } else {
+            return "You lose! :( ";
+        }
+    }
+
+    public static String getRandomChoice() {
+        String[] options = {"rock", "paper", "scissors"};
+        Random random = new Random();
+        return options[random.nextInt(options.length)];
+    }
+}

src/test/java/com/thealgorithms/puzzlesandgames/RockPaperScissorsTest.java

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+package com.thealgorithms.puzzlesandgames;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+class RockPaperScissorsTest {
+
+    @Test
+    void testGetResultTie() {
+        assertEquals("It's a tie!", RockPaperScissors.getResult("rock", "rock"));
+    }
+
+    @Test
+    void testGetResultWin() {
+        assertEquals("You win! :D ", RockPaperScissors.getResult("rock", "scissors"));
+    }
+
+    @Test
+    void testGetResultLose() {
+        assertEquals("You lose! :( ", RockPaperScissors.getResult("rock", "paper"));
+    }
+
+    @Test
+    void testGetRandomChoiceIsValid() {
+        String choice = RockPaperScissors.getRandomChoice();
+        assertTrue(choice.equals("rock") || choice.equals("paper") || choice.equals("scissors"));
+    }
+}