usaco_beads

/* ID:mingcha1 PROG: beads LANG: C++ */ #include<iostream> #include<string> #include<fstream> using namespace std; ofstream fout ("beads.out"); ifstream fin ("beads.in"); const int SIZE=1000; struct node{ int len,pos; }a[SIZE]; int main(){ string str; int n; fin>>n>>str; str+=str; char cur=str[0]; int num=0; a[num].pos=0; for(int i=1;str[i];++i){ if(cur!=str[i] && str[i]!='w'){ a[num].len=i-a[num].pos; a[++num].pos=i; cur=str[i]; } } a[num].len=n*2-a[num].pos; //fout<<str<<endl; //for(int i=0;i<=num;++i){ // fout<<a[i].len<<endl; //} for(int i=1;i<=num;++i){ for(int j=a[i].pos-1; j>=0 &&str[j]=='w';--j){ a[i].len++; if(a[i].len>n) a[i].len=n; } }//modify /*fout<<"asdf/n"; for(int i=0;i<=num;++i){ fout<<a[i].len<<endl; }*/ int max=-1,pos=0,flag=0; for(int i=0;i<=num;++i){ if(a[i].len+a[i+1].len>=max){ if(a[i].len+a[i+1].len==max){ if(str[a[i+1].pos-1]!='w'){ pos=a[i+1].pos; } } else{ max=a[i].len+a[i+1].len; pos=a[i+1].pos; } } } /*cout<<"===="<<endl; cout<<pos<<endl;*/ for(int i=pos-1;i>=0 &&str[i]=='w';--i) flag++; if(num!=0){ if(max-flag<=n) fout<<max-flag<<endl; else fout<<n<<endl; } else{ if(a[0].len<=n) fout<<a[0].len<<endl; else fout<<n<<endl; } } //333 //rwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwbrwb