// Program to test solutions to problem #8 on the cse142 midterm, spring 2018.

import java.util.*;

public class Q8Verifier {
    // **ENTER YOUR SOLUTION HERE**
    public static int filter(int num, int d) {

    }

    // this is the sample solution
    public static int filterSln(int num, int d) {
         int result = 0;
         int multiplier = 1;
         while (num > 0) {
            int dig = num % 10;
            if (dig != d) {
               result += multiplier * dig;
               multiplier *= 10;
            }
            num /= 10;
         }
         return result;
    }

    private static int count, failCount;
    private static Random r;

    public static final int ERRORS_MAX = 20;

    public static void main(String[] args) {
        failCount = 0;
        r = new Random();
        for (int i = 1; i <= 8; i++) {
            test(i);
        }
        if (failCount == 0) {
            System.out.println("PASSED all " + count + " tests");
        }
    }
    
    // public/private kickoff: i represents size of number to test in digits
    public static void test(int i) {
        int[] data = new int[i];
        test(data, 0);
    }

    // private half: if check is base case where we have generated
    // a number, stored in data, that we want to test.
    // 
    // else branch is a recursive case to pick numbers that
    // contain spurts of the same digits, of differing lengths
    private static void test(int[] data, int index) {
        if (index == data.length) {
	    for (int d = 0; d < 10; d++) {
                count++;
                int num = 0;
                for (int i = 0; i < data.length; i++) {
                   num *= 10;
                   num += data[i];
                }
                boolean fail = false;
                RuntimeException except = null;
                int result1 = 0, result2 = 0;
                try {
                     System.out.println("Testing num = " + num + ", d = " + d);
                     result1 = filter(num, d);
                } catch (RuntimeException e) {
                    fail = true;
                    except = e;
                }
                result2 = filterSln(num, d);
                fail = fail || result1 != result2;
                if (fail) {
                    if (except != null) {
                        StackTraceElement[] trace = except.getStackTrace();
                        int line = trace[0].getLineNumber();
                        System.out.println("FAIL with exception for num=" + 
                                           num + ", d=" + d + " at line#"
                                           + line);
                    } else {
                        System.out.println("FAIL for num=" + num + ", d=" + d);
                    }
                    System.out.println("Correct: " + result2);
                    System.out.println("Theirs:  " + result1);
                    System.out.println();
                    failCount++;
                    if (failCount > ERRORS_MAX) {
                        System.out.println("exceeds " + ERRORS_MAX + " errors");
                        System.out.println("with " + count + " correct");
                        System.exit(0);
                    }
                }
	    }
        } else {
            for (int i = 1; i <= data.length - index; i++) {
               int digit = r.nextInt(10);
               for (int j = index; j < index + i; j++) {
                  data[j] = digit;
               }
               test(data, index + i);
            }
            data[index] = r.nextInt(10);
            test(data, index + 1);
        }
    }
}