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make/test/Queens.java@09d92cbb793b (annotated)

make/test/Queens.java

Thu, 06 Jan 2011 20:10:19 -0800

author

cl

date

Thu, 06 Jan 2011 20:10:19 -0800

changeset 2385

09d92cbb793b

parent 1907

c18cbe5936b8

permissions

-rw-r--r--

Added tag jdk7-b124 for changeset 0a8e0d4345b3

duke@435	1	/*
trims@1907	2	* Copyright (c) 2006, 2008, Oracle and/or its affiliates. All rights reserved.
duke@435	3	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435	4	*
duke@435	5	* This code is free software; you can redistribute it and/or modify it
duke@435	6	* under the terms of the GNU General Public License version 2 only, as
duke@435	7	* published by the Free Software Foundation.
duke@435	8	*
duke@435	9	* This code is distributed in the hope that it will be useful, but WITHOUT
duke@435	10	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435	11	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
duke@435	12	* version 2 for more details (a copy is included in the LICENSE file that
duke@435	13	* accompanied this code).
duke@435	14	*
duke@435	15	* You should have received a copy of the GNU General Public License version
duke@435	16	* 2 along with this work; if not, write to the Free Software Foundation,
duke@435	17	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435	18	*
trims@1907	19	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
trims@1907	20	* or visit www.oracle.com if you need additional information or have any
trims@1907	21	* questions.
duke@435	22	*
duke@435	23	*/
duke@435	24
duke@435	25	import java.util.*;
duke@435	26
duke@435	27	// Copyright 1996, Animorphic Systems
duke@435	28	// gri 28 Aug 92 / 15 Jan 93 / 8 Dec 95
duke@435	29
duke@435	30	class Queens {
duke@435	31
duke@435	32	static void try_i(boolean a[], boolean b[], boolean c[], int x[], int i) {
duke@435	33	int adj = 7;
duke@435	34
duke@435	35	for (int j = 1; j <= 8; j++) {
duke@435	36	if (b[j] && a[i+j] && c[adj+i-j]) {
duke@435	37	x[i] = j;
duke@435	38	b[j] = false;
duke@435	39	a[i+j] = false;
duke@435	40	c[adj+i-j] = false;
duke@435	41	if (i < 8) try_i(a, b, c, x, i+1);
duke@435	42	else print(x);
duke@435	43	b[j] = true;
duke@435	44	a[i+j] = true;
duke@435	45	c[adj+i-j] = true;
duke@435	46	}
duke@435	47	}
duke@435	48	}
duke@435	49
duke@435	50	public static void main(String s[]) {
duke@435	51	boolean a[] = new boolean[16+1];
duke@435	52	boolean b[] = new boolean[ 8+1];
duke@435	53	boolean c[] = new boolean[14+1];
duke@435	54	int x[] = new int[8+1];
duke@435	55	int adj = 7;
duke@435	56
duke@435	57	for (int i = -7; i <= 16; i++) {
duke@435	58	if (i >= 1 && i <= 8) b[i] = true;
duke@435	59	if (i >= 2) a[i] = true;
duke@435	60	if (i <= 7) c[adj+i] = true;
duke@435	61	}
duke@435	62
duke@435	63	x[0] = 0; // solution counter
duke@435	64
duke@435	65	try_i(a, b, c, x, 1);
duke@435	66	}
duke@435	67
duke@435	68	static void print(int x[]) {
duke@435	69	// first correct solution: A1 B5 C8 D6 E3 F7 G2 H4
duke@435	70
duke@435	71	char LF = (char)0xA;
duke@435	72	char CR = (char)0xD;
duke@435	73
duke@435	74	x[0]++;
duke@435	75	if (x[0] < 10)
duke@435	76	System.out.print(" ");
duke@435	77	System.out.print(x[0] + ". ");
duke@435	78	for (int i = 1; i <= 8; i++) {
duke@435	79	char p = (char)('A' + i - 1);
duke@435	80	System.out.print(p);
duke@435	81	System.out.print (x[i] + " ");
duke@435	82	}
duke@435	83	System.out.println();
duke@435	84	}
duke@435	85
duke@435	86	};