• Substring Uva 11468_记忆化搜索 + AC自动机


    Code:

    #include<cstdio>
    #include<cstring>
    #include<queue>
    using namespace std;
    const int maxn=100;
    const int maxd=400+3;
    const int sigma=65;
    double d[maxd][103],perc[sigma+3];
    int ch[maxd][sigma+1],end1[maxd],f[maxd],last[maxd];
    char A[30],mapp[sigma+3];
    int cnt;
    queue<int>Q;
    int idx(char s){
    	if(s>='a'&&s<='z')return s-'a';
    	if(s>='A'&&s<='Z')return s-'A'+26;
    	return s-'0'+52;
    }
    struct V
    {
    	void insert(char p[]){
    		int n=strlen(p);
    		int cur=0;
    		for(int i=0;i<n;++i){
    			int c=idx(p[i]);
    			if(!ch[cur][c])ch[cur][c]=++cnt;
    			cur=ch[cur][c];
    		}
    		end1[cur]=1,last[cur]=1;
    	}
    	void getfail(){
    	   for(int i=0;i<sigma;++i)if(ch[0][i])Q.push(ch[0][i]);
    		while(!Q.empty()){
    			int r=Q.front();Q.pop();
    			for(int i=0;i<sigma;++i){
    				int u=ch[r][i];
    				if(!u){ch[r][i]=ch[f[r]][i];continue;}
    				Q.push(u);
    				int v=f[r];
    				while(v&&!ch[v][i])v=f[v];
    				f[u]=ch[v][i];
    				if(last[f[u]])last[u]=1;
    			}
    		}
    	}                  
    	double dp(int j,int L,int l,int n){
    		if(end1[j]||last[j])return 0.0;
    		if(L==l)return 1.0;
    		if(d[j][L]>=0)return d[j][L];
    		double ans=0.0;
    		for(int i=1;i<=n;++i){
    			int c=idx(mapp[i]);
    			ans+=perc[i]*dp(ch[j][c],L+1,l,n);
    		}
    		d[j][L]=ans;
    		return ans;
    	}
    }AC;
    int main(){
    	int T;scanf("%d",&T);
    	for(int cas=1;cas<=T;++cas)
    	{
    	   memset(end1,0,sizeof(end1)); memset(d,-1,sizeof(d));
    	   memset(f,0,sizeof(f)); memset(last,0,sizeof(last));
    	   memset(ch,0,sizeof(ch));
    	   cnt=0;
    	   int k;scanf("%d",&k);
    	   for(int i=1;i<=k;++i){scanf("%s",A);AC.insert(A);}
    	   int n;scanf("%d",&n);char g=getchar();
    	   for(int i=1;i<=n;++i)
    	   	{scanf("%c",&mapp[i]); scanf("%lf",&perc[i]);g=getchar();}
    	   int l;scanf("%d",&l);
    	   AC.getfail();
    	   double ans=AC.dp(0,0,l,n);
    	   printf("Case #%d: ",cas);
    	   printf("%.6f
    ",ans);
    	 }
    	return 0;
    }
    

      

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  • 原文地址:https://www.cnblogs.com/guangheli/p/9845160.html
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