1 /* $OpenBSD: odds.c,v 1.7 2016/01/08 13:40:05 tb Exp $ */
2
3 /*
4 * Copyright (c) 1980, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32 #include "back.h"
33
34 void
odds(int r1,int r2,int val)35 odds(int r1, int r2, int val)
36 {
37 int i, j;
38
39 if (r1 == 0) {
40 for (i = 0; i < 6; i++)
41 for (j = 0; j < 6; j++)
42 table[i][j] = 0;
43 return;
44 } else {
45 r1--;
46 if (r2-- == 0) {
47 for (i = 0; i < 6; i++) {
48 table[i][r1] += val;
49 table[r1][i] += val;
50 }
51 } else {
52 table[r2][r1] += val;
53 table[r1][r2] += val;
54 }
55 }
56 }
57
58 int
count(void)59 count(void)
60 {
61 int i, j, total;
62
63 total = 0;
64 for (i = 0; i < 6; i++)
65 for (j = 0; j < 6; j++)
66 total += table[i][j];
67 return(total);
68 }
69
70 int
canhit(int i,int c)71 canhit(int i, int c)
72 {
73 int j, k, b;
74 int a, diff, place, addon, menstuck;
75
76 if (c == 0)
77 odds(0, 0, 0);
78 if (board[i] > 0) {
79 a = -1;
80 b = 25;
81 } else {
82 a = 1;
83 b = 0;
84 }
85 place = abs(25 - b - i);
86 menstuck = abs(board[b]);
87 for (j = b; j != i; j += a) {
88 if (board[j] * a > 0) {
89 diff = abs(j - i);
90 addon = place + ((board[j] * a > 2 || j == b) ? 5 : 0);
91 if ((j == b && menstuck == 1) ||
92 (j != b && menstuck == 0))
93 for (k = 1; k < diff; k++)
94 if (k < 7 && diff - k < 7 &&
95 (board[i + a * k] * a >= 0 ||
96 board[i + a * (diff - k)] >= 0))
97 odds(k, diff - k, addon);
98 if ((j == b || menstuck < 2) && diff < 7)
99 odds(diff, 0, addon);
100 }
101 if (j == b && menstuck > 1)
102 break;
103 }
104 return(count());
105 }
106