TMD这些神奇的猴子。。。
DP里面用KMP的next的数组来搞一搞，（不是很会，一开始想这样搞，然而思路很乱，就弃疗了，，，DP太虚了）
1 #include<bits/stdc++.h> 2 #define N 1000005 3 #define LL long long 4 #define inf 0x3f3f3f3f 5 using namespace std; 6 inline int ra() 7 { 8 int x=0,f=1; char ch=getchar(); 9 while (ch<'0' || ch>'9') {if (ch=='-') f=-1; ch=getchar();} 10 while (ch>='0' && ch<='9') {x=x*10+ch-'0'; ch=getchar();} 11 return x*f; 12 } 13 const int MAXN = 30; 14 char s[MAXN]; 15 int fail[MAXN]; 16 int n,m,L; 17 char c[MAXN]; 18 double p[MAXN]; 19 double dp[1010][MAXN]; 20 void cal() 21 { 22 fail[1]=0; int fix=0; 23 for (int i=2; i<=L; i++) 24 { 25 while (fix && s[fix+1]!=s[i]) fix=fail[fix]; 26 if (s[fix+1]==s[i]) fix++; 27 fail[i]=fix; 28 } 29 } 30 int main() 31 { 32 while (scanf("%d %d ",&m,&n)) 33 { 34 memset(dp,0,sizeof(dp)); 35 if (!m && !n) break; 36 for (int i=1; i<=m; i++) scanf("%c %lf ",&c[i],&p[i]); 37 scanf("%s",s+1); 38 L=strlen(s+1); cal(); 39 dp[0][0]=1; 40 for (int i=0; i<n; i++) 41 for (int j=0; j<L; j++) 42 for (int k=1; k<=m; k++) 43 { 44 int fix=j; 45 while (fix && s[fix+1]!=c[k]) fix=fail[fix]; 46 if (s[fix+1]==c[k]) fix++; 47 dp[i+1][fix]+=dp[i][j]*p[k]; 48 } 49 double ans=0; 50 for (int i=0; i<=n; i++) ans+=dp[i][L]; 51 printf("%.2lf%% ",ans*100);//system("pause"); 52 } 53 return 0; 54 }