1157 : 단어 공부 [C++]

#include <iostream>

using namespace std;

int main()
{
 int Alphabet[26] = { 0, };
 char Input[1000001];
 cin >> Input;

 for (int i = 0; Input[i] != NULL; i++)
 {
  if (Input[i] >= 'a')
   Alphabet[(int)(Input[i] - 'a')]++;
  else if (Input[i] >= 'A')
   Alphabet[(int)(Input[i] - 'A')]++;
  else
   continue;
 }

 int Most = 0;
 for (int i = 0; i < 2; i++)
 {
  for (int j = 0; j < 26; j++)
  {
   if (Most == j)
    continue;
   else if (Alphabet[Most] <= Alphabet[j])
   {
    Most = j;
    if (i > 0)
    {
     Most = -1;
     break;
    }
   }
  }
 }

 if (Most == -1)
  cout << "?" << endl;
 else
  cout << (char)(Most+'A') << endl;
}