2014-09-24 14:45:10 +00:00
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/*
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!!DESCRIPTION!! solves the "8 queens" chess problem
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!!ORIGIN!! LCC 4.1 Testsuite
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!!LICENCE!! own, freely distributeable for non-profit. read CPYRIGHT.LCC
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*/
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2014-11-22 17:28:05 +00:00
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#include <stdio.h>
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2014-09-24 14:45:10 +00:00
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int up[15], down[15], rows[8], x[8];
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void queens(int c);
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void print(void);
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int main(void)
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{
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int i;
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for (i = 0; i < 15; i++)
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up[i] = down[i] = 1;
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for (i = 0; i < 8; i++)
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rows[i] = 1;
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queens(0);
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return 0;
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}
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void queens(int c)
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{
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int r;
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for (r = 0; r < 8; r++)
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if (rows[r] && up[r-c+7] && down[r+c]) {
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rows[r] = up[r-c+7] = down[r+c] = 0;
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x[c] = r;
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if (c == 7)
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print();
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else
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queens(c + 1);
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rows[r] = up[r-c+7] = down[r+c] = 1;
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}
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}
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void print(void)
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{
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int k;
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for (k = 0; k < 8; k++) {
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printf("%c", x[k]+'1');
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if(k<7) printf(" ");
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}
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printf("\n");
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}
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