// Program to test solutions to problem #4 on the cse143x midterm, fall 2024.
// Fill in your solution to undouble, then compile and run the program.

import java.util.*;

public class Test4 {
    public static String undouble(String s) {
        // fill in your solution here
        // you can also rename the parameter above
    }

    // this is the sample solution
    public static String undouble2(String s) {
        if (s.length() < 2) {
            return s;
        } else if (s.charAt(0) == s.charAt(1)) {
            return s.charAt(0) + undouble2(s.substring(2));
        } else {
            return s.charAt(0) + undouble2(s.substring(1));
        }
    }

    private static int testCount;
    private static int failCount;

    public static final int ERRORS_MAX = 25;

    public static void main(String[] args) {
        test("");
        test("m");
        test("nn");
        test("pq");
        test("sstt");
        test("odegaard");
        test("bookkeeper");
        test("baz");
        test("foobar");
        test("mississippi");
        test("apple");
        test("carry");
        test("berry");
        test("aardvark");
        test("glass");
        test("committment");
        test("juggle");
        test("little");
        test("cac");
        test("theses");
        test("ccaatt");
        test("aabbccddeeffgg");
        test2("", 6);

        if (failCount == 0) {
            System.out.println("passed all tests");
        } else {
            System.out.println("failed " + failCount + " of " + testCount + 
                               " tests");
        }
    }

    public static void test2(String s, int len) {
        if (!s.contains("aaa") && !s.contains("bbb") && !s.contains("ccc") &&
            !s.contains("ddd") && !s.contains("eee")) {
            test(s);
        }
        if (len > 0) {
            for (char ch = 'a'; ch <= 'e'; ch++) {
                String s2 = s + ch;
                test2(s2, len - 1);
            }
        }
    }

    public static void test(String s) {
        System.out.println("testing undouble(\"" + s + "\")");
        String result1 = undouble2(s);
        boolean fail = false;
        try {
            String result2 = undouble(s);
            if (!result1.equals(result2)) {
                fail = true;
                System.out.println("result should be \"" + result1 +
                                   "\", yours = \"" + result2 + "\"");
            }
        } catch (RuntimeException e) {
            int line = e.getStackTrace()[1].getLineNumber();
            System.out.println("threw " + e + " at line #" + line);
            fail = true;
        }
        testCount++;
        if (fail) {
            System.out.println("failed");
            failCount++;
            if (failCount > ERRORS_MAX) {
                System.out.println("exceeds " + ERRORS_MAX + " errors");
                System.out.println("with " + testCount + " correct");
                System.exit(0);
            }
        } else {
            System.out.println("passed");
        }
        System.out.println();
    }
}