重做 USACO 1.1 黑色星期五

/*
LANG: C
ID: zqynux11
PROG: beads
*/
#include <stdio.h>
#include <string.h>

char ball[701];

int main(void)
{
	int max = 0;
	int a = 0, b = 0, w = 0;		/*  */
	int i, n;
	char ch = '\0';
	freopen("beads.in", "r", stdin);
	freopen("beads.out", "w", stdout);
	scanf("%d\n", &n);

	gets(ball);
	memmove(ball + n, ball, sizeof(char)*n);
	for(i = 0; i < 2 * n && max < n; i++){
		if(ball[i] == 'w'){
			w++;
			b++;
		}else if(ball[i] != ch){
			ch = ball[i];
			if(a + b > max){
				max = a + b;
			}
			a = b - w;
			b = w + 1;
			w = 0;
		}else{
			w = 0;
			b++;
		}
	}
	if(a + b > max){		/* 之前没考虑到rrr这类只有一种珠子的一些特殊情况 */
		max = a + b;
	}
	printf("%d\n", max > n ? n : max);
	return 0;
}