queens.c
2.68 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
#include <stdio.h>
#include <string.h>
#include <fcntl.h>
#include <errno.h>
#include "fdc_int.h"
#ifndef NMAX
# define NMAX MAX_VARIABLES // maximum number of queens
#endif
static int N = 11; // actual number of queens
int main(int argc, char *argv[])
{
fd_int queens[NMAX];
int solutions = 0, one_solution = 1;
int i, j;
int seed;
int dev_random;
fd_init(&argc, &argv);
for (i = 1; i < argc; ++i)
if (!strcmp(argv[i], "--all"))
one_solution = 0;
else
{
N = atoi(argv[i]);
break;
}
if (N > NMAX)
_fd_fatal("queens: more than NMAX queens requested");
#ifdef LOCAL_SEARCH
#if 01
seed = time(0);
seed = 1206987119;
//seed = 1207917731; // N = 6, best improvement termina
//seed = 0;
#else
if ((dev_random = open("/dev/urandom", O_RDONLY)) == -1)
_fd_fatal("/dev/urandom: %s\n", strerror(errno));
read(dev_random, &seed, sizeof(seed));
#endif
srandom(seed);
_fd_debug("seed = %u\n", seed);
#endif
/*
FORWARD_CHECKING REBENTA(VA) (N == 6)
queens[0] = fd_new(2, 5);
_fd_val_del_val(5, queens[0]->domain);
queens[N - 1] = fd_new(6, 6);
*/
for (j = ++i, i = 0; j < argc; ++j, ++i)
{
int lb, ub;
char *p;
lb = ub = atoi(argv[j]) - 1;
if (p = strchr(argv[j], '-'))
ub = atoi(p + 1) - 1;
queens[i] = fd_new(lb, ub);
}
for (; i < N; ++i)
queens[i] = fd_new(0, N - 1);
#if 0
fd_fake_all_different(queens, N);
#elif 01
fd_all_different(queens, N);
#else
for (i = 0; i < N; ++i)
fd_exactly_one(queens, N, i + 1);
#endif
for (i = 0; i < N; ++i)
for (j = i + 1; j < N; ++j)
fd_minus_ne(queens[i], queens[j], i - j);
for (i = 0; i < N; ++i)
for (j = i + 1; j < N; ++j)
fd_minus_ne(queens[i], queens[j], j - i);
while (fd_solve() == FD_OK)
{
int value;
printf("solution %d:\n", ++solutions);
for (i = 0; i < N; ++i)
if (fd_var_single(queens[i], &value))
printf("%d%c", value + 1, (i < N - 1) ? ' ' : '\n');
else
{
int j;
_fd_error("\nsolution contains non-singleton variable\n");
for (j = 0; j < N; ++j)
{
fd_print(queens[j]);
#if defined(FORWARD_CHECKING) && 0
printf("\t(%d)", queens[i]->epoch);
putchar('\n');
}
#else
putchar(' ');
}
putchar('\n');
#endif
break;
}
#if !(defined(LOCAL_SEARCH) || defined(DISTRIBUTED_SOLVER))
if (one_solution)
#endif
break;
}
fd_end();
{
// avoid failure messages from mpirun
extern int _fd_counting_solutions; // XXX: private variable
if (_fd_counting_solutions)
return 0;
}
if (solutions)
printf("%d solutions found\n", solutions);
else
printf("inconsistent CSP\n");
return !solutions;
}