BZOJ 1398: Vijos1382寻找主人 Necklace【字符串最小表示

#include<bits/stdc++.h>
#define MAXN 1000057
using namespace std;	int n,n2;
char a[MAXN<<1],b[MAXN<<1];
char c[MAXN];
int calc(char *s){
int i,j,k;
for(i=0,j=1,k=0;i<n2&&j<n2;k=0){
while(s[i+k]==s[j+k]&&k<n2)	++k;
if(k==n2)	break;
if(s[i+k]>s[j+k])	i+=k+1;
else	j+=k+1;
if(i==j)	++i;
}
return min(i,j);
}
int main(){
scanf("%s%s",a,b);
n=strlen(a);
for(int i=0;i<n;++i)	a[i+n]=a[i],b[i+n]=b[i];
a[n<<1]=b[n<<1]='\0';
n=strlen(a);
n2=n>>1;
int id_a=calc(a),id_b=calc(b);
for(int i=id_a,j=id_b;i<id_a+n2&&j<id_b+n2;++i,++j)
if(a[i]!=b[j])	return puts("No"),0;
puts("Yes");
for(int i=id_a;i<id_a+n2;++i)	putchar(a[i]);
return 0;
}