POJ 1322 機率DP

#include<cstdio>#include<cstring>#define LL __int64const int LMT=55;LL dp[LMT][LMT];bool is[LMT][LMT];void init(void){    memset(is,0,sizeof(is));    memset(dp,0,sizeof(dp));}LL gcd(LL a,LL b){    return b?gcd(b,a%b):a; }int main(void){    int n,m,i,j,cnt,x,y;    LL base,tem;    char sec[LMT];    while(~scanf("%d%d",&n,&m)){       getchar();        m++;       init();        base=0;      for(i=1;i<=n;i++)  {         gets(sec);         cnt=0;      for(j=0;sec[j];j++)  {        if(sec[j]=='*'||sec[j]=='.')++cnt;        if(sec[j]=='*')is[i][cnt]=1;  }}    is[0][0]=1;    for(i=1;i<=n+1;i++)is[n+1][i]=1;    dp[0][0]=1;   for(i=0;i<=n;++i)     for(j=0;j<=i;++j)     if(is[i][j])    {        x=i+1;y=j;                   if(y)     while(x<=n+1&&y<=x)     {          if(is[x][y])  {             dp[x][y]+=(1<<(x-i-1))*dp[i][j];             break;  }      x+=2;++y;     }     x=i+1;y=j+1;     while(x<=n+1&&y<=x)     {        if(is[x][y]){          dp[x][y]+=(1<<(x-i-1))*dp[i][j];          break;}         x+=2;++y;     }    }    for(i=1;i<=n+1;i++)base+=dp[n+1][i];   tem=gcd(dp[n+1][m],base);   printf("%I64d",dp[n+1][m]/tem);   printf("/");   printf("%I64d",base/tem);   printf("\n"); } return 0;}