记录编号	360339	评测结果	AAAAAAAAAA
题目名称	[HEOI 2015]小Z的房间	最终得分	100
用户昵称	sxysxy	是否通过	通过
代码语言	C++	运行时间	0.010 s
提交时间	2016-12-29 13:22:15	内存使用	0.60 MiB

#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <string>
#include <list>
#include <queue>
#include <vector>
#include <cctype>
#include <algorithm>
using namespace std;
namespace IO
{
char buf[1<<18], *fs, *ft;
inline char readc()
{
    return (fs==ft&&(ft=(fs=buf)+fread(buf,1,1<<18,stdin),fs==ft))?0:*fs++;
}
inline int fast_read()
{
    int r;
    char c;
    bool s = false;
    while(c = readc())
    {
        if(c >= '0' && c <= '9')
        {
            r = c^0x30;
            break;
        }else if(c == '-')s = true;
    }
    while(isdigit(c = readc()))
        r = (r<<3)+(r<<1)+(c^0x30);
    return s?-r:r;
}

}using IO::fast_read;using IO::readc;
int n, m;
char z[12][12];
void getstr(char *s, int t)
{
    char c = readc();
    while(isspace(c))c = readc();
    s[0] = c;
    for(int i = 1; i < t; i++)
        s[i] = readc();
}
typedef long long LL;
const LL mod = 1e9;
LL a[90][90], s[12][12], S;
LL gs()
{
    S--;
    for(int i = 1; i <= S; i++)for(int j = 1; j <= S; j++)
        a[i][j] = (a[i][j]+mod)%mod;
    LL ans = 1;
    for(int j = 1; j <= S; j++)
    {
        for(int i = j+1; i <= S; i++)
        {
            while(a[i][j])
            {
                LL t = a[j][j]/a[i][j];
                for(int k = j; k <= S; k++)
                {
                    a[j][k] = ((a[j][k]-t*a[i][k])%mod+mod)%mod;
                    swap(a[i][k], a[j][k]);
                }
                ans *= -1;
            }
        }
        ans = ans*a[j][j]%mod;
    }
    return (ans+mod)%mod;
}
int main()
{
    freopen("room.in", "r", stdin);
    freopen("room.out", "w", stdout);
    n = fast_read(); m = fast_read();
    for(int i = 1; i <= n; i++)
        getstr(z[i]+1, m);
            //外圈补上墙
    for(int i = 0; i <= n+1; i++)for(int j = 0; j <= m+1; j++)
        if(!i || !j || i==n+1 || j==m+1)z[i][j] = '*';
    for(int i = 1; i <= n; i++)for(int j = 1; j <= m; j++)
    {
        if(z[i][j] == '.')
        {
            s[i][j] = ++S;
            if(z[i-1][j] == '.')a[s[i-1][j]][s[i][j]] = a[s[i][j]][s[i-1][j]] = 1;
            if(z[i][j-1] == '.')a[s[i][j-1]][s[i][j]] = a[s[i][j]][s[i][j-1]] = 1;
        }
    }
    for(int i = 1; i <= S; i++)for(int j = 1; j <= S; j++)
        if(a[i][j] && i != j)a[i][i]++;
    printf("%lld\n", gs());
    return 0;
}