标签:max kmp power ble void pac class map ret
大概就是字符串匹配加一个字符串哈希判重。懒得打kmp,就用字符串哈希匹配了。
字符串哈希大概就是把字符串转成一个p进制的数,每一段字符串都有一个对应的哈希值。p尽量取质数
#include<bits/stdc++.h>
using namespace std;
#define ull unsigned long long
const int N=2005;
const int pr=131;
ull power[N],h[N],b,e;
char t[N],sb[N],se[N];
int tx,ty,x[N],y[N],lt,lb,le,ans;
void pre() {
power[0]=1;
for(int i=1; i<=lt; ++i)
power[i]=power[i-1]*pr,h[i]=h[i-1]*pr+t[i]-'a'+1;
for(int i=1; i<=lb; ++i)b=b*pr+sb[i]-'a'+1;
for(int i=1; i<=le; ++i)e=e*pr+se[i]-'a'+1;
}
ull has(int l,int r) {
return h[r]-h[l-1]*power[r-l+1];
}
unordered_map<ull,bool>mp;
int main() {
scanf("%s%s%s",t+1,sb+1,se+1);
lt=strlen(t+1);
lb=strlen(sb+1);
le=strlen(se+1);
pre();
for(int i=1; i<=lt-lb+1; ++i)
if(has(i,i+lb-1)==b)x[++tx]=i;
for(int i=le; i<=lt; ++i)
if(has(i-le+1,i)==e)y[++ty]=i;
for(int i=1; i<=tx; ++i)
for(int j=1; j<=ty; ++j)
if(x[i]<=y[j]&&y[j]-x[i]+1>=max(le,lb))
{
ull ha=has(x[i],y[j]);
if(!mp[ha])++ans,mp[ha]=true;
}
printf("%d\n",ans);
return 0;
}
标签:max kmp power ble void pac class map ret
原文地址:https://www.cnblogs.com/zzctommy/p/12318245.html