bzoj 4556 字符串

后缀数组，暴力硬跑
贼快

 #include<cstdio>
 #include<cstring>
 #include<iostream>
 #include<algorithm>
 #include<cmath>
 #define MAXN 100005
 using namespace std;
 int buc[MAXN],wa[MAXN],wb[MAXN];
 int r[MAXN],sa[MAXN],rank[MAXN],height[MAXN];
 void getheight(int n){
     int i,j,k=;
     for(i=;i<n;i++)rank[sa[i]]=i;
     for(i=;i<n;height[rank[i++]]=k)
         for(k?k--:,j=sa[rank[i]-];r[i+k]==r[j+k];k++);
     return ;
 }
 bool cmp(int *c,int a,int b,int d)
     {return c[a]==c[b]&&c[a+d]==c[b+d];}
 void da(int n,int m=){
     int i,j,p,*x=wa,*y=wb,*t;
     for(i=;i<m;i++)buc[i]=;
     for(i=;i<n;i++)buc[x[i]=r[i]]++;
     for(i=;i<m;i++)buc[i]+=buc[i-];
     for(i=n-;~i;i--)sa[--buc[x[i]]]=i;
     for(j=,p=;p<n;j*=,m=p){
         for(i=n-j,p=;i<n;i++)y[p++]=i;
         for(i=;i<n;i++)if(sa[i]>=j)y[p++]=sa[i]-j;
         for(i=;i<m;i++)buc[i]=;
         for(i=;i<n;i++)buc[x[y[i]]]++;
         for(i=;i<m;i++)buc[i]+=buc[i-];
         for(i=n-;~i;i--)sa[--buc[x[y[i]]]]=y[i];
         for(t=x,x=y,y=t,p=,x[sa[]]=,i=;i<n;i++)
             x[sa[i]]=cmp(y,sa[i-],sa[i],j)?p-:p++;
     }
     getheight(n);
     return ;
 }
 int n,q;
 char s[MAXN];
 int main(){
     scanf("%d%d",&n,&q);
     scanf("%s",s);
     for(int i=;i<n;i++)r[i]=s[i];
     da(n+);
     int ans,minn,pos,now,a,b,c,d;
     while(q--){
         scanf("%d%d%d%d",&a,&b,&c,&d);
         a--;b--;c--;d--;
         ans=; minn=min(d-c+,b-a+);
         pos=rank[c];
         if(sa[pos]>=a&&sa[pos]<=b)ans=max(ans,min(minn,min(b-sa[pos]+,d-c+)));
         minn=min(minn,height[pos]);
         for(int i=pos-;i>=;i--){
             if(minn<=ans)break;
             now=sa[i];
             if(now>=a&&now<=b)ans=max(ans,min(minn,min(b-sa[i]+,d-c+)));
             minn=min(minn,height[i]);
         }
         minn=min(d-c+,b-a+);
         for(int i=pos+;i<=n;i++){
             minn=min(minn,height[i]);
             if(minn<=ans)break;
             now=sa[i];
             if(now>=a&&now<=b){ans=max(ans,min(minn,min(b-sa[i]+,d-c+)));}
         }
         printf("%d\n",ans);
     }
     return ;
 }