TaroFillingAStringDiv2.cpp

class TaroFillingAStringDiv2 {
    public:

  int getNumber(string S) {
    if(S.size()<2)
      return 0;
    int ans=0;
    int i=0;
    while(S[i]=='?')
      i++;

    for (; i < s.size(); i++) {
      if(S[i]=='?')
        {
          if(S[i-1]=='A')
            S[i]=='B';
          else
            S[i]=='A';
        }
      if(s[i-1]==s[i])
        ans++;
    }
    return ans;
  }

};