[c++] 백준 알고리즘 공부 1157번

#include <iostream>
#include <map>
#include <string>
using namespace std;

map<char, int> arr;

int main() {

	string a;
	cin >> a;
	
	for (int i = 0; i < a.size(); i++)
	{
		if ('a' <= a[i] && a[i] <= 'z')
			a[i] -= 32;
	}

	char T;
	int max = 0;
	for (int i = 0; i < a.size(); i++)
	{
		T = a[i];
		arr[T]++;
		if (max < arr[T])
			max = arr[T];
	}
	int cnt = 0;
	char answer;
	for (int i = 65; i <=90; i++)
	{
		if (max == arr[i]) {
			cnt++;
			answer = char(i);
		}
	}

	if (cnt == 1)
		cout << answer;
	else
		cout << "?";
}