算法: 枚举

#include<bits/stdc++.h>
using namespace std;

const int N = 710;
char s[N];
int n;

int main()
{
    //freopen("beads.in","r",stdin);
    //freopen("beads.out","w",stdout);

    scanf("%d", &n); //getchar();
    scanf("%s", s + 1); 

    for(int i = n + 1; i <= 2 * n; i ++) s[i] = s[i - n];//破环成链

    int ans = 0;
    for(int i = 1; i <= n; i++)
    {
        char now = s[i];
        int lsum = 0, rsum = 0;
        for(int j = i; j <= i + n - 1; j++) 
        {
            if(now == 'w') lsum ++, now = s[j];
            else 
            {
                if(s[j] == now || s[j] == 'w') lsum ++;
                else break;
            }
        }

        now = s[i + n - 1];
        for(int j = i + n - 1; j >= i; j--)
        {
            if(now == 'w') rsum ++, now = s[j];
            else 
            {
                if(s[j] == now || s[j] == 'w') rsum ++;
                else break;
            }
        }

        int res = lsum + rsum;
        if(res > n) res = n;
        ans = max(res, ans);
    }

    printf("%d", ans);
    return 0;
}