C++(씨쁠쁠)(cplusplus)-백준(baekjoon)(BaekJoon)코딩 1157번:단어공부 답

#include <iostream>
#include <string>
int arr[26];
using namespace std;
int main() {
    int cnt = 0,  big = 0, index;
    string word;
    cin >> word;
    
    for (int i = 0; i < word.size(); i++)
    {
        if (word[i] >= 65 && word[i] <= 90)
        {
            arr[word[i] - 65]++;
        }
        else if (word[i] >= 97 && word[i] <= 122)
        {
            arr[word[i] - 97]++;
        }
    }
    for (int i = 0; i < 26; i++)
    {
        if (arr[i] > big)
        {
            big = arr[i];
            index = i;
        }
        
    }
    for (int i = 0; i < 26; i++)
    {
        if (arr[i] == big)
        {
            cnt++;
            if (cnt >= 2)
            {
                cout << "?" << '\n';
                return 0;
            }
        }    
    }
    cout << (char)(index + 65);
}