feat: RoleCountHelper can indicate how many player in a role easily

src/main/java/com/lapisberry/utils/RoleCountHelper.java

@@ -0,0 +1,34 @@
+package com.lapisberry.utils;
+
+public final class RoleCountHelper {
+    public static int getEmperors(int players) {
+        if (4 <= players && players <= 8) return 1;
+        return 0;
+    }
+
+    public static int getRoyalists(int players) {
+        if (4 <= players && players <= 8) return TABLE[players - 4][2];
+        return 0;
+    }
+
+    public static int getRebels(int players) {
+        if (4 <= players && players <= 8) return TABLE[players - 4][1];
+        return 0;
+    }
+
+    public static int getSpies(int players) {
+        if (4 <= players && players <= 8) return TABLE[players - 4][0];
+        return 0;
+    }
+
+    // Array of role count
+    private static final int[][] TABLE = {// sp,rb,ry -> spy, rebel, royalist
+            {1, 2, 0},// 4 players
+            {1, 2, 1},// 5 players
+            {1, 3, 1},// 6 players
+            {1, 3, 2},// 7 players
+            {2, 3, 2},// 8 players
+            {2, 4, 2},// 9 players
+            {2, 4, 3} // 10 players
+    };
+}