UVa12545 - Bits Equalizer

//UVa12545 - Bits Equalizer
//贪心
#include<iostream>
#define MIN(X,Y) (((X)>(Y))?(Y):(X))
using namespace std;

int main(){
  //freopen("UVa12545.in","r",stdin);
  int N, kase = 0;  
  cin>>N;
  while(N--){
    string S,T;
    int count = 0, bit[6];
    bit[0] = bit[1] = bit[2] = bit[3] = bit[4] = 0;
    cin>>S>>T;
    for(int i = 0; i<S.size(); i++){
      bit[T[i] -'0'+4]++;//all T[0]; 
      if(S[i] != T[i])
        if(S[i] == '?'){ count++; continue;}
        else {bit[S[i]-'0']++; continue;}
      bit[S[i]-'0'+2]++;//相等时候的s[0];
    }
    if(bit[2]+bit[0]+count < bit[4]){ cout<<"Case "<<++kase<<": -1\n"; continue;}
    count += bit[0]+bit[1]-MIN(bit[0],bit[1]);
    cout<<"Case "<<++kase<<": "<<count<<"\n";
  }
  return 0;
}
//已AC