C :

#include<stdio.h>
int main()
{
    int i,k,j,o,n,sum,x,y,p,q;
    char a[10000],g,f;
    while(scanf("%d",&n)!=EOF)
    {
        sum=0;
        scanf("%s",a);
		for(i=0;i<n;i++)
		{
			a[i+n]=a[i];
		}
        for(i=n;i<=2*n;i++)
        {
			k=x=y=p=q=0;
            for(j=i;j<=2*n;j++)
            {
			    if(a[j]!='w')
				{
                	f=a[j];
					break;
				}
			}
			for(o=i-1;o>=0;o--)
            {
			    if(a[o]!='w')
				{
                	g=a[o];
					break;
				}
			}
			if(g!=f)
			{
				for(j=i;j<2*n;j++)
				{
			        if(a[j]=='w'||a[j]==f)
					    k++;
			    	else
				    	break;
				}
                for(o=i-1;o>=0;o--)
				{
			        if(a[o]=='w'||a[o]==g)
					    k++;
				    else
					    break;
				}
			}
            else
			{
				for(j=i;j<2*n;j++)
				{
			        if((a[j]=='w'||a[j]==f)&&p==0)
					    k++;
			    	else
					{
				    	x++;
						p=1;
						if(a[j+1]==f)
							break;
					}
				}
				for(o=i-1;o>=0;o--)
				{
			        if((a[o]=='w'||a[o]==g)&&q==0)
					    k++;
				    else
					{
						y++;
						q=1;
						if(a[o-1]==g)
							break;
					}
				}
				if(x>y)
					k=k+x;
				else
					k=k+y;
			}
            if(k>sum)
            sum=k;
        }
		if(sum>n)
			sum=n;
        printf("%d\n",sum);
    }
    return 0;
}

C++ :

/*
ID:wangzhe30
LANG:C
PROG:beads
*/
#include <stdio.h>
int main()
{
	int n;
	//freopen("beads.in","r",stdin);
	//freopen("beads.out","w",stdout);
	while(scanf("%d",&n)!=EOF)
	{
	    int k[350]={0},i,t,max=0,f=0,p,h;
        char beads[700]={0};
	    scanf("%s",beads);
        for(i=0;i<n;i++)
            beads[i+n]=beads[i];
        for(i=0;i<n;i++)
        {
            p=i;
            f=0;
            for(t=0;t<n;t++)
            {
                if(beads[p]=='w' && f==0)
                {
                    k[i]++;
                    p++;
                    continue;
                }
                if((beads[p]==beads[p+t])||(beads[p+t]=='w'))
                {
                    f=1;
                    k[i]++;
                }
                else
                    break;
            }
            f=0;
            p=n+i-1;
            for(h=0;h<n-t;h++)
            {
                if(beads[p]=='w' && f==0)
                {
                    k[i]++;
                    p--;
                    continue;
                }
                if((beads[p]==beads[n+i-1-h])||(beads[n+i-1-h]=='w'))
                {
                    f=1;
                    k[i]++;
                }
                else
                    break;
            }
        }
        for(i=0;i<n;i++)
            if (max<k[i])
                max=k[i];
        printf("%d\n",max);
	}
	return 0;
}