BZOJ 4327 JSOI2012 玄武密码（后缀自动机）

#include <cstdio>
#include <cstring>
#include <algorithm>
#include <vector>
using namespace std;
const int N=20000010;
char s
;
int cal(char c){
if(c=='S')return 1;
if(c=='N')return 2;
if(c=='E')return 3;
if(c=='W')return 0;
}
struct sam{
int p,q,np,nq,cnt,last,a
[4],l
,f
;
sam(){cnt=0;last=++cnt;}
void extend(int c){
p=last;np=last=++cnt;l[np]=l[p]+1;
while(!a[p][c]&&p)a[p][c]=np,p=f[p];
if(!p)f[np]=1;
else{
q=a[p][c];
if(l[p]+1==l[q])f[np]=q;
else{
nq=++cnt;l[nq]=l[p]+1;
memcpy(a[nq],a[q],sizeof(a[q]));
f[nq]=f[q]; f[np]=f[q]=nq;
while(a[p][c]==q)a[p][c]=nq,p=f[p];
}
}
}
void build(){
scanf("%s",s+1);
int len=strlen(s+1);
for(int i=1;i<=len;i++)extend(cal(s[i]));
}
void solve(){
scanf("%s",s+1);
int len=strlen(s+1);
int p=1,ans=0;
for(int i=1;i<=len;i++){
int c=cal(s[i]);
if(a[p][c])p=a[p][c],ans++;
else break;
}printf("%d\n",ans);
}
}sam;
int n,m;
int main(){
scanf("%d%d",&m,&n);
sam.build();
for(int i=1;i<=n;i++)sam.solve();
return 0;
}