/**
 * Find the longest common prefix of the command line arguments
 * In several different ways
 * 
 * G Towell
 * Nov 2023
 */

public class Activity17 {
    public static void main(String[] args) {
        main_justFirst(args);
        main_all(args);
        main_first_func(args);
        main_all_func(args);
    }

    public static void main_justFirst(String[] args) {
        String first = args[0];
        int longest = 0;
        for (int i = 1; i < first.length(); i++) {
            String prefix = first.substring(0, i);
            for (int j = 1; j < args.length; j++) {
                if (args[j].startsWith(prefix)) {
                    longest = i;
                    break;
                }
            }
        }
        System.out.println(longest);
    }

    public static void main_all(String[] args) {
        int longest = 0;
        for (int z = 0; z < args.length; z++) {
            String first = args[z];
            for (int i = 1; i < first.length(); i++) {
                String prefix = first.substring(0, i);
                for (int j = 0; j < args.length; j++) {
                    if (j != z && args[j].startsWith(prefix)) {
                        if (i > longest) {
                            longest = i;
                        }
                        break;
                    }
                }
            }
        }
        System.out.println("ALL: " + longest);
    }

    public static void main_first_func(String[] args) {
        int longest = prefixer(args, 0);
        System.out.println("prefix 0: " + longest);
    }

    public static void main_all_func(String[] args) {
        int longest = 0;
        for (int z = 0; z < args.length; z++) {
            int l = prefixer(args, z);
            if (l > longest) {
                longest = l;
            } 
        }
        System.out.println("prefix all: " + longest);
    }

    public static int prefixer(String[] args, int z) {
        String first = args[z];
        int longest = 0;
            for (int i = 1; i < first.length(); i++) {
                String prefix = first.substring(0, i);
                for (int j = 0; j < args.length; j++) {
                    if (j != z && args[j].startsWith(prefix)) {
                        if (i > longest) {
                            longest = i;
                        }
                        break;
                    }
                }
                if (longest != i) {
                    break;
                }
            }
            return longest;
    }
}