洛谷 P1203 [USACO1.1]坏掉的项链Broken Necklace

坏掉的项链Broken Necklace

难度：★

Code:

#include <iostream>
#include <cstdio>
#include <cstring>
#include <string>
using namespace std;
//Mystery_Sky
//
#define M 1000
string s;
int n, ans, flag, maxx, sum;
int l[M], r[M];
bool it[M];

int main() {
    scanf("%d", &n);
    cin >> s;
    for(int i = 0; i < n; i++) {
        sum = 2;
        int iter_1, iter_2;
        char ster_1, ster_2;
        iter_1 = i-1, iter_2 = i+2;
        if(iter_1 < 0) iter_1 = n;
        if(iter_2 >= n) iter_2 -= n;
        ster_1 = s[i], ster_2 = s[i+1];
        while(!ans) {
//			printf("iter_1=%d\n", iter_1);
            if(s[iter_1] == s[iter_1+1]) sum++;
            else if(s[iter_1] == 'w') sum++;
            else if(s[iter_1] == ster_1) sum++;
            else if(ster_1 == 'w') {
                sum++;
                ster_1 = s[iter_1];
            }
            else break;
            iter_1--;
            if(iter_1 < 0) iter_1 = n-1;
            if(iter_1 == iter_2-1) ans = n;
        }
        while(!ans) {
            if(s[iter_2] == s[iter_2-1]) sum++;
            else if(s[iter_2] == 'w') sum++;
            else if(s[iter_2] == ster_2) sum++;
            else if(ster_2 == 'w') {
                sum++;
                ster_2 = s[iter_2];
            }
            else break;
            iter_2++;
            if(iter_2 >= n) iter_2 = 0;
        }
        if(ans) break;
        maxx = max(sum, maxx);
    }
    if(ans == n) printf("%d\n", ans);
    else if(maxx > n) printf("%d\n", n);
    else printf("%d\n", maxx);
    return 0;

}