自己的usaco代码---PROB Broken Necklace

/*
ID: 输你自己的
PROG: beads
LANG: C++
*/
#include<iostream>
#include<cstdio>
#include<cstring>
#include<string>
#include<algorithm>
#include<cmath>
using namespace std;
int n,f[400],ans=0;
char a[1200];
int main()
{
memset(a,'#',sizeof(a));
freopen("beads.in","r",stdin);
freopen("beads.out","w",stdout);
cin>>n;
for(int i=1;i<=n;i++)
cin>>a[i];
for(int i=n+1;i<=n+n;i++)
a[i]=a[i+n]=a[i-n];
char x='w';
for(int i=1+n;i<=n*2;i++)
{
int k=i;
f[i-n]=2;
x='w';
while((a[++k]==a[k-1]||a[k]=='w'||a[k-1]=='w'||a[k]==x)&&k<n+i-1){
if(a[k-1]=='w'&&a[k]!='w'&&x!='w'&&a[k]!=x) break;

f[i-n]++;
if(a[k]=='w') x=a[k-1];
if(a[k-1]=='w'&&x=='w'&&a[k]!=x) x=a[k];
}
int t=k-n*2;
x='w';
k=i-1;
while((a[--k]==a[k+1]||a[k]=='w'||a[k+1]=='w'||a[k]==x)&&k>n+t){
if(a[k+1]=='w'&&a[k]!='w'&&a[k]!=x&&x!='w') break;
f[i-n]++;
if(a[k]=='w'&&a[k+1]!='w') x=a[k+1];
if(a[k+1]=='w'&&a[k]==x&&x!='w') x=a[k];
}
}
for(int i=1;i<=n;i++)
ans=max(ans,f[i]);
cout<<ans<<endl;
return 0;

}