Bzoj4820 [Sdoi2017]硬币游戏

 1 #include<iostream>
 2 #include<algorithm>
 3 #include<cstring>
 4 #include<cstdio>
 5 #include<cmath>
 6 using namespace std;
 7 const int mxn=305;
 8 int read(){
 9     int x=0,f=1;char ch=getchar();
10     while(ch<‘0‘ || ch>‘9‘){if(ch==‘-‘)f=-1;ch=getchar();}
11     while(ch>=‘0‘ && ch<=‘9‘){x=x*10+ch-‘0‘;ch=getchar();}
12     return x*f;
13 }
14 double f[mxn][mxn];
15 double p[mxn];
16 void Gauss(int n){
17     int i,j;
18     for(i=1;i<=n;i++){
19         int p=i;
20         for(j=i+1;j<=n;j++)  if(fabs(f[j][i])>fabs(f[p][i]))p=j;
21         if(p!=i)for(j=i;j<=n+1;j++)swap(f[i][j],f[p][j]);
22         for(j=n+1;j>=i;j--)  f[i][j]/=f[i][i];
23         for(j=1;j<=n;j++){
24             if(j==i)continue;
25             double tmp=f[j][i];
26             for(int k=1;k<=n+1;k++)
27                 f[j][k]-=f[i][k]*tmp;
28         }
29     }
30     return;
31 }
32 int nxt[mxn];
33 char s[mxn][mxn];
34 int n,m;
35 void getfail(int id){
36     nxt[1]=0;
37     for(int i=2,j=0;i<=m;i++){
38         while(j && s[id][i]!=s[id][j+1])j=nxt[j];
39         if(s[id][j+1]==s[id][i])j++;
40         nxt[i]=j;
41     }
42     return;
43 }
44 void KMP(int id){
45     for(int i=1;i<=n;i++){//和所有串匹配 
46         int j=0;
47         for(int k=1;k<=m;k++){
48             while(j && s[id][j+1]!=s[i][k])j=nxt[j];
49             if(s[id][j+1]==s[i][k])j++;
50         }
51         for(;j;j=nxt[j])f[id][i]+=p[m-j];//,printf("%d to %d :%.5f\n",id,i,p[m-j]);
52     }
53     f[id][n+1]=-p[m];
54     f[n+1][id]=1.0;
55     return;
56 }
57 void Print(){
58     for(int i=1;i<=n+1;i++){
59         for(int j=1;j<=n+2;j++){
60             printf("%.4lf ",f[i][j]);
61         }
62         puts("");
63     }
64     return;
65 }
66 int main(){
67     int i,j;
68     n=read();m=read();
69     p[0]=1.0;
70     for(i=1;i<=m;i++)p[i]=p[i-1]*0.5;
71     for(i=1;i<=n;i++)scanf("%s",s[i]+1);
72     for(i=1;i<=n;i++){
73         getfail(i);
74         KMP(i);
75     }
76     f[n+1][n+2]=1.0;
77 //  Print();
78     Gauss(n+1);
79     for(int i=1;i<=n;i++)
80         printf("%.10f\n",f[i][n+2]);
81     return 0;
82 }
83