POJ2758 Checking the Text 哈希

注意到插入次数挺少的，于是每次暴力重构，然后哈希+二分

#include<cstdio>
#include<iostream>
#include<algorithm>
#include<cstring>
#include<cmath>
#include<cctype>
#include<cstdlib>
#include<vector>
#include<queue>
#include<map>
#include<set>
#define ll unsigned long long
#define R register int
using namespace std;
namespace Fread {
    static char B[1<<15],*S=B,*D=B;
    #define getchar() (S==D&&(D=(S=B)+fread(B,1,1<<15,stdin),S==D)?EOF:*S++)
    inline int g() {
        R ret=0,fix=1; register char ch; while(!isdigit(ch=getchar())) fix=ch=='-'?-1:fix;
        do ret=ret*10+(ch^48); while(isdigit(ch=getchar())); return ret*fix;
    }
}using Fread::g;
const int N=50210,B=131;
int len,m,n,pos[N],x; 
ll hsh[N],p[N];
char s[N],op[2];
inline void HSH(int st) {for(R i=st;i<=len;++i) hsh[i]=hsh[i-1]*B+s[i]-96;}
inline ll calc(int l,int r) {return hsh[r]-hsh[l-1]*p[r-l+1];}
inline ll query(int x,int y) {
    R l=0,r=len-max(x,y)+1;
    while(l<r) {
        R md=l+r+1>>1;
        if(calc(x,x+md-1)==calc(y,y+md-1)) l=md;
        else r=md-1;
    } return l;
}
signed main() {
#ifdef JACK
    freopen("NOIPAK++.in","r",stdin);
#endif
    scanf("%s%d",s+1,&m); len=n=strlen(s+1); HSH(1); 
    for(R i=1;i<=n;++i) pos[i]=i; p[0]=1; for(R i=1;i<=N-10;++i) p[i]=p[i-1]*B;
    for(R i=1;i<=m;++i) {
        scanf("%s",op); if(op[0]=='I') {
            scanf("%s%d",op,&x); if(x>len) x=len+1;
            memcpy(s+x+1,s+x,sizeof(char)*(len-x+1));
            s[x]=op[0]; for(R j=n;j>=1;--j) {
                if(pos[j]<x) break; ++pos[j];
            } ++len; HSH(x);
        } else { R x,y;
            scanf("%d%d",&x,&y);
            printf("%d
",query(pos[x],pos[y]));
        }
    }        
} 

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2019.06.10