[src/trunk]: src/games/gomoku gomoku: announce tie as early as possible

[rillig <rillig%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/aa9296432b20
branches:  trunk
changeset: 366462:aa9296432b20
user:      rillig <rillig%NetBSD.org@localhost>
date:      Sat May 28 07:58:35 2022 +0000

description:
gomoku: announce tie as early as possible

diffstat:

 games/gomoku/makemove.c |  21 ++++++++++++++-------
 1 files changed, 14 insertions(+), 7 deletions(-)

diffs (49 lines):

diff -r 0ff6727f6b2b -r aa9296432b20 games/gomoku/makemove.c
--- a/games/gomoku/makemove.c   Sat May 28 06:25:35 2022 +0000
+++ b/games/gomoku/makemove.c   Sat May 28 07:58:35 2022 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: makemove.c,v 1.29 2022/05/28 06:25:35 rillig Exp $     */
+/*     $NetBSD: makemove.c,v 1.30 2022/05/28 07:58:35 rillig Exp $     */
 
 /*
  * Copyright (c) 1994
@@ -34,7 +34,7 @@
 
 #include <sys/cdefs.h>
 /*     @(#)makemove.c  8.2 (Berkeley) 5/3/95   */
-__RCSID("$NetBSD: makemove.c,v 1.29 2022/05/28 06:25:35 rillig Exp $");
+__RCSID("$NetBSD: makemove.c,v 1.30 2022/05/28 07:58:35 rillig Exp $");
 
 #include "gomoku.h"
 
@@ -50,6 +50,17 @@
 
 static void update_overlap(struct spotstr *);
 
+static bool
+is_tie(void)
+{
+
+       for (int y = 1; y <= BSZ; y++)
+               for (int x = 1; x <= BSZ; x++)
+                       if (board[PT(x, y)].s_wval != 0)
+                               return false;
+       return true;
+}
+
 /*
  * Return values:
  *     MOVEOK  everything is OK.
@@ -199,11 +210,7 @@
 
        update_overlap(&board[mv]);
 
-       /*
-        * TODO: Declare a tie as soon as all frames are blocked. This is
-        *  usually much earlier than when the whole board is filled.
-        */
-       if (nmoves == BSZ * BSZ)
+       if (is_tie())
                return TIE;
 
        return MOVEOK;