88 lines
2.0 KiB
C++
88 lines
2.0 KiB
C++
#include<cstdio>
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#include<cstring>
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#include<queue>
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using namespace std;
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#define MAX 1005
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int cnt;
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struct node
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{
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int flag;
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int next[26],fail;
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} head[MAX];
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queue<int> q;
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double pt[30],dp[MAX][30];
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void build(char *s,int idx)
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{
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int len=strlen(s),k;
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for(int i=0; i<len; ++i)
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{
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k=s[i]-'a';
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if(head[idx].next[k]==0)
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head[idx].next[k]=(cnt++);
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idx=head[idx].next[k];
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}
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head[idx].flag=1;
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}
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void build_fail(int idx)
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{
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int now;
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queue<int> q;
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head[idx].fail=0;
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q.push(idx);
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for(; !q.empty();)
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{
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now=q.front();
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q.pop();
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for(int i=0; i<26; ++i)
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if(head[now].next[i])
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{
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if(now==0) head[head[now].next[i]].fail=0;
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else head[head[now].next[i]].fail=head[head[now].fail].next[i];
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q.push(head[now].next[i]);
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}
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else
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{
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if(now==0) head[now].next[i]=0;
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else head[now].next[i]=head[head[now].fail].next[i];
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}
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}
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}
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int main()
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{
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int n,m,v;
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double t;
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char s[1005];
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for(; scanf("%d%d",&n,&m);)
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{
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if(n+m==0) break;
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memset(pt,0,sizeof(pt));
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memset(dp,0,sizeof(dp));
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memset(head,0,sizeof(head));
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cnt=1;
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for(int i=1; i<=n; ++i)
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{
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scanf("%s%lf",s,&t);
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pt[s[0]-'a']=t;
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}
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scanf("%s",s);
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build(s,0);
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build_fail(0);
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dp[0][0]=1;
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for(int i=0; i<m; ++i)
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for(int j=0; j<cnt-1; ++j)
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if(i>=j)
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{
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for(int k=0; k<26; ++k)
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{
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v=head[j].next[k];
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dp[i+1][v]+=(dp[i][j]*pt[k]);
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}
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}
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double ans=0;
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for(int i=0; i<=m; i++)
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ans+=dp[i][cnt-1];
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printf("%.2f%%\n",ans*100);
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}
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return 0;
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}
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