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/*
* N-Queens Problem Solver
* Found somewhere on the Internet; can't remember where. Possibly Wikipedia.
*/
#include <stdio.h>
#include <stdbool.h>
#include <stdlib.h>
#include "hardinfo.h"
#include "benchmark.h"
#define QUEENS 11
int row[QUEENS];
bool safe(int x, int y)
{
int i;
for (i = 1; i <= y; i++)
if (row[y - i] == x || row[y - i] == x - i || row[y - i] == x + i)
return false;
return true;
}
int nqueens(int y)
{
int x;
for (x = 0; x < QUEENS; x++) {
if (safe((row[y - 1] = x), y - 1)) {
if (y < QUEENS) {
nqueens(y + 1);
} else {
break;
}
}
}
return 0;
}
static gpointer nqueens_for(unsigned int start, unsigned int end, void *data, gint thread_number)
{
unsigned int i;
for (i = start; i <= end; i++) {
nqueens(0);
}
return NULL;
}
void
benchmark_nqueens(void)
{
gdouble elapsed = 0;
shell_view_set_enabled(FALSE);
shell_status_update("Running N-Queens benchmark...");
elapsed = benchmark_parallel_for(0, 10, nqueens_for, NULL);
bench_results[BENCHMARK_NQUEENS] = elapsed;
}
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