【BZOJ】【P2258】【pku2758 Checking the Text 文本校对】【题解】【hash】

传送门:http://www.lydsy.com/JudgeOnline/problem.php?id=2258

明天就初赛了

刷水娱♂乐身心

Code:

#include<cstdio>
#include<cctype>
#include<cstring>
#include<iostream>
#include<algorithm>
using namespace std;
const int maxn=50300;
typedef unsigned long long UL;
UL base=233;
UL hash[maxn];
UL hash_l[maxn];
char s[maxn];
int len,m;
void hash_init(int be){
UL val=hash[be-1];
for(int i=be;i<=len;i++){
val=val*base+s[i]-'a';
hash[i]=val;
}
}
int mp[maxn+200];
int main(){
scanf("%s",s+1);s[0]='#';
len=strlen(s+1);hash_l[0]=1;
for(int i=1;i<=len+200;i++)hash_l[i]=hash_l[i-1]*base,mp[i]=i;
scanf("%d",&m);
hash_init(1);
while(m--){
char op=getchar();while(op!='Q'&&op!='I')op=getchar();
if(op=='I'){
char x=getchar();while(!isalpha(x))x=getchar();
int ps;scanf("%d",&ps);if(ps>len)ps=len+1;
for(int i=len+1;i>ps;i--)s[i]=s[i-1];
for(int j=lower_bound(mp+1,mp+1+len,ps)-mp,i=j;i<=len+1;i++)mp[i]++;
s[ps]=x;len++;s[len+1]='\0';
hash_init(ps);
}else{
int a,b;scanf("%d%d",&a,&b);a=mp[a];b=mp[b];
int l=0,r=len-b+2;
while(l<r){
int mid=(l+r)>>1;
if(hash[a+mid-1]-hash[a-1]*hash_l[mid]==hash[b+mid-1]-hash[b-1]*hash_l[mid])
l=mid+1;
else r=mid;
}printf("%d\n",l-1);
}
}
return 0;
}