就当做模板了

#include <iostream>

#include <cstdio>

using namespace std;

const int maxn=500010;

char s[maxn];

int minxp(int len)

{

int i=0,j=1,k=0;

while(i<len&&j<len&&k<len)

{

int t=s[(i+k)%len]-s[(j+k)%len];

if(t==0) k++;

else

{

if(t>0) i+=k+1;

else j+=k+1;

if(i==j) j++;

k=0;

}

}

return min(i,j);

}

int main()

{

int ca,len;

cin>>ca;

while(ca--)

{

cin>>len>>s;

int s1=minxp(len);

cout<<s1<<endl;

}

return 0;

}