USACO 1.2 Broken Necklace

断点是白色的情况在做题的时候完全没有想到呢...

看到了数据才发现这个问题$qwq$

 /*
 ID:Starry21
 LANG:C++
 TASK:beads
 */
 #include<iostream>
 #include<string>
 #include<cstdio>
 #include<cstring>
 #include<map>
 using namespace std;
 #define N 355
 int n,ans;
 char s[N*];
 int l,r;
 int f2(char c)
 {
     int res=;
     while()
     {
         if(s[l+]==c||s[l+]=='w')
             l++,res++;
         else break;
         if(l+==r) break;
     }
     return res;
 }
 int f1()
 {
     int res1=,res2=;
     int ll=l;char c='b';
     while()
     {
         if(s[l+]==c||s[l+]=='w')
             l++,res1++;
         else break;
         if(l+==r) break;
     }
     c='r';
     while()
     {
         if(s[ll+]==c||s[ll+]=='w')
             ll++,res2++;
         else break;
         if(ll+==r) break;
     }
     if(res2>res1) l=ll;
     return max(res1,res2);
 }
 int f4(char c)
 {
     int res=;
     while()
     {
         if(s[r-]==c||s[r-]=='w')
             r--,res++;
         else break;
         if(l+==r) break;
     }
     return res;
 }
 int f3()
 {
     int res1=,res2=;
     int rr=r;char c='b';
     while()
     {
         if(s[r-]==c||s[r-]=='w')
             r--,res1++;
         else break;
         if(l+==r) break;
     }
     c='r';
     while()
     {
         if(s[rr-]==c||s[rr-]=='w')
             rr--,res2++;
         else break;
         if(l+==rr) break;
     }
     if(res2>res1) r=rr;
     return max(res1,res2);
 }
 int main()
 {
     //freopen("beads.in","r",stdin);
     //freopen("beads.out","w",stdout);
     scanf("%d",&n);
     scanf("%s",s+);
     for(int i=;i<=n;i++)
         s[i+n]=s[i];
     for(int i=;i<=n;i++)
     {
         l=i,r=i+n-;
         int cnt1=,cnt2=;
         char c=s[l];
         if(c!='w') cnt1+=f2(c);
         else cnt1+=f1();
         if(l+==r)
         {
             ans=max(ans,cnt1+/*还要加上端点r*/);
             continue;
         }
         //----
         c=s[r];
         if(c!='w') cnt1+=f4(c);
         else cnt1+=f3();
         ans=max(ans,cnt1+cnt2);
     }
     printf("%d\n",ans);
     return ;
 }
 /*
 77
 rwrwrwrwrwrwrwrwrwrwrwrwbwrwbwrwrwrwrwrwrwrwrwrwrwrwrwrwrwrwrwrwrwrwrwrwrwrwr
 */