[java] 1032. 명령 프롬프트

import java.io.*;
import java.util.*;

public class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        int N = Integer.parseInt(br.readLine());

        String[] words = new String[N];
        for (int i=0 ; i< words.length ; i++) {
            words[i] = br.readLine();
        }

        int minLength = Integer.MAX_VALUE;

        for (String word : words) {
            minLength = Math.min(minLength, word.length());
        }

        StringBuilder output = new StringBuilder();

        for (int i=0 ; i<minLength ; i++) {
            char currentChar = words[0].charAt(i);
            boolean isSame = true;

            for (String word : words) {
                if (word.charAt(i) != currentChar) {
                    isSame = false;
                    break;
                }
            }
            if (isSame) {
                output.append(currentChar);
            } else {
                output.append('?');
            }
        }
        System.out.println(output.toString());
        br.close();
    }
}