34 lines
1.2 KiB
C++
34 lines
1.2 KiB
C++
#include <cstdio>
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#include <cstdlib>
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#include <cstring>
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#include <algorithm>
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using namespace std;
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const int MAX_N = 8, MAX_S = 1 << MAX_N;
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int n, m, t, dp[MAX_S][MAX_S];
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char g[MAX_N][MAX_N + 1];
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int main() {
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while (scanf("%d", &n) != EOF) {
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if (!n) break;
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for (int i = 0; i < n; i ++) {
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scanf("%s", g[i]);
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for (int j = 0; j < n; j ++) g[i][j] -= '0';
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}
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int upper = 1 << n, ans = 0;
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for (int i = 0; i < n; i ++) {
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memset(dp, 0, sizeof(dp));
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dp[1 << i][1 << i] = 1;
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for (int mask = 0; mask < upper; mask ++)
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for (int s = mask; s; s = (s - 1) & mask)
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for (int u = 0; u < n; u ++) if (mask & (1 << u))
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for (int v = 0; v < n; v ++) if ((mask & (1 << v)) == 0 && g[u][v]) {
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int m1 = mask | (1 << v);
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int m2 = (s | (1 << v)) & (~(1 << u));
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if (((1 << (v + 1)) - 1) >= m2) dp[m1][m2] += dp[mask][s];
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}
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for (int s = 0; s < upper; s ++) ans += dp[upper - 1][s];
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}
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printf("%d\n", ans);
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}
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return 0;
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}
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