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/*
!!DESCRIPTION!! solves the "8 queens" chess problem
!!ORIGIN!! LCC 4.1 Testsuite
!!LICENCE!! own, freely distributeable for non-profit. read CPYRIGHT.LCC
*/
#include <stdio.h>
int up[15], down[15], rows[8], x[8];
void queens(int c);
void print(void);
int main(void)
{
int i;
for (i = 0; i < 15; i++)
up[i] = down[i] = 1;
for (i = 0; i < 8; i++)
rows[i] = 1;
queens(0);
return 0;
}
void queens(int c)
{
int r;
for (r = 0; r < 8; r++)
if (rows[r] && up[r-c+7] && down[r+c]) {
rows[r] = up[r-c+7] = down[r+c] = 0;
x[c] = r;
if (c == 7)
print();
else
queens(c + 1);
rows[r] = up[r-c+7] = down[r+c] = 1;
}
}
void print(void)
{
int k;
for (k = 0; k < 8; k++) {
printf("%c", x[k]+'1');
if(k<7) printf(" ");
}
printf("\n");
}
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