Backend/shuffle #135 (#142)

Co-authored-by: aprilywy <[email protected]>

packages/backend/domain/src/main/java/tw/waterballsa/gaas/citadels/util/CitadelsUtils.java

@@ -0,0 +1,20 @@
+package tw.waterballsa.gaas.citadels.util;
+
+import java.util.List;
+import java.util.Random;
+
+public class CitadelsUtils {
+
+    public static <T> void shuffle(List<T> cards) {
+        Random rd = new Random();
+
+        for (int i = cards.size() - 1; i > 0; i--) {
+            int j = rd.nextInt(i + 1);
+
+            T temp = cards.get(i);
+            cards.set(i, cards.get(j));
+            cards.set(j, temp);
+        }
+    }
+}
+