POJ1321(状压DP)

数据比较小，怎么暴力都行。

#include <cstdio>#include <cstring>#include <cmath>#include <iostream>#include <algorithm>using namespace std;#define maxn 1<<8#define maxm 8111111int n, kk;char mp[11][11];long long dp[11][maxn]; //放到第i行 状态为j 已经放置k个棋子的种数int board[11]; // 第i行的状态int num[maxn], state[maxn], cnt;int get (int x) { //x二进制1的个数    int ans = 0;    while (x) {        if (x&1)            ans++;        x >>= 1;    }    return ans;}bool ok (int x) {    if (x == 0)        return 1;    for (int i = 1; i < (1<<n); i <<= 1) {        if (x == i)            return 1;    }    return 0;}int main () {    //freopen ("in", "r", stdin);    for (int i = 0; i < maxn; i++) {        num[i] = get (i);    }    cnt = 0; state[++cnt] = 0;    for (int i = 0; i <= 7; i++) {        state[++cnt] = (1<<i);    }    while (scanf ("%d%d", &n, &kk) == 2) {        if (n == kk && n == -1)            break;        for (int i = 0; i < n; i++) {            scanf ("%s", &mp[i]);            board[i] = 0;            for (int j = 0; j < n; j++) {                board[i] = (board[i]<<1) + (mp[i][j] == '#' ? 0 : 1);            }        }        memset (dp, 0, sizeof dp);        for (int i = 1; i <= cnt && state[i] < (1<<n); i++) {            if (board[0]&state[i])                continue;            dp[0][state[i]] = 1;        }        for (int i = 1; i < n; i++) {            for (int j = 0; j < (1<<n); j++) {                for (int y = 1; y <= cnt && state[y] < (1<<n); y++) {                    int k = state[y];                    if (j&k)                        continue;                    if (board[i]&k)                        continue;                    dp[i][k^j] += dp[i-1][j];                }            }        }        long long ans = 0;        for (int i = 0; i < (1<<n); i++) {            if (num[i] == kk)                ans += dp[n-1][i];        }        printf ("%lld\n", ans);    }    return 0;}