백준 1475번: 방 번호

문제 출처: https://www.acmicpc.net/problem/1475

import java.io.BufferedReader;
import java.io.InputStreamReader;
 
public class Main {
    public static void main(String[] args) throws Exception {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        String N = reader.readLine();
        int[] number = new int[10];
        
        for(int i=0 ; i<N.length() ; i++)
            number[N.charAt(i)-'0']++; // 0-9 개수 카운트
        
        int result = 0;
        int sixNine = (number[6]+number[9]) / 2 + (number[6]+number[9]) % 2; // 6과 9 계산
        
        for(int i=0 ; i<10 ; i++){
            if(i==6 || i==9)
                continue;
            
            if(result < number[i])
                result = number[i];
        }
        
        if(result < sixNine)
            result = sixNine;
        
        System.out.println(result);
    }
}