Add RockPaperScissors game implementation (Jokenpo)

Author: ligiastalves

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

@@ -0,0 +1,70 @@
+package com.thealgorithms.puzzlesandgames;
+
+import java.util.Random;
+import java.util.Scanner;
+
+/**
+ * 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 class RockPaperScissors {
+
+    public static void main(String[] args) {
+        Scanner scanner = new Scanner(System.in);
+        Random random = new Random();
+
+        String[] options = {"rock", "paper", "scissors"};
+
+        System.out.println("=== Rock Paper Scissors Game ===");
+        System.out.println("Type 'rock', 'paper', or 'scissors'. Type 'exit' to quit.");
+
+        while (true) {
+            System.out.print("\nYour choice: ");
+            String userChoice = scanner.nextLine().trim().toLowerCase();
+
+            if (userChoice.equals("exit")) {
+                System.out.println("Thanks for playing! ");
+                break;
+            }
+
+            // Validate input
+            if (!userChoice.equals("rock") && !userChoice.equals("paper") && !userChoice.equals("scissors")) {
+                System.out.println("Invalid choice! Try again.");
+                continue;
+            }
+
+            // Computer chooses randomly
+            String computerChoice = options[random.nextInt(3)];
+            System.out.println("Computer chose: " + computerChoice);
+
+            // Determine result
+            String result = getResult(userChoice, computerChoice);
+            System.out.println(result);
+        }
+
+        scanner.close();
+    }
+
+    private 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! :( ";
+        }
+    }
+}