// Program to test solutions to problem #4 on the cse143 midterm, spring 2018.
// The methods code1/code2/code3/code4 have the sample solution to the four
// coding problems.  Replace the code with your own code to test it.

public class Test4 {
    public static void code1() {
        p = q.next.next;
        q.next.next = null;
    }

    public static void code2() {
        q.next.next = q;
        q = q.next;
        q.next.next = null;
    }

    public static void code3() {
        q.next.next = p.next;
        p.next = q;
        q = p;
        p = q.next.next;
        q.next.next = null;
    }

    public static void code4() {
        p.next.next.next = p;
        q.next.next = p.next.next;
        p.next.next = q;
        q = q.next;
        p = p.next;
        p.next.next = null;
        q.next.next.next = null;
    }

    public static void main(String[] args) {
        passCount = 0;
        problem1();
        problem2();
        problem3();
        problem4();
        System.out.println("Passed " + passCount + " of 4 tests");
    }

    private static ListNode p, q;
    private static int passCount;

    public static void problem1() {
        p = null;
        q = new ListNode(1, new ListNode(2, new ListNode(3)));
        doProblem(1, "p->[3]", "q->[1]->[2]");
    }

    public static void problem2() {
        p = new ListNode(1);
        q = new ListNode(2, new ListNode(3));
        doProblem(2, "p->[1]", "q->[3]->[2]");
    }

    public static void problem3() {
        p = new ListNode(1, new ListNode(2));
        q = new ListNode(3, new ListNode(4));
        doProblem(3, "p->[4]->[2]", "q->[1]->[3]");
    }

    public static void problem4() {
        p = new ListNode(1, new ListNode(2, new ListNode(3)));
        q = new ListNode(4, new ListNode(5));
        doProblem(4, "p->[2]->[4]", "q->[5]->[3]->[1]");
    }

    public static void doProblem(int n, String answer1, String answer2) {
        System.out.println("Problem #" + n + ":");
        System.out.println("before:");
        System.out.println("  " + text(p, "p"));
        System.out.println("  " + text(q, "q"));

        boolean threwException = false;
        try {
            if (n == 1) {
                code1();
            } else if (n == 2) {
                code2();
            } else if (n == 3) {
                code3();
            } else if (n == 4) {
                code4();
            } else {
                System.out.println("unknown problem number");
            }
        } catch (Exception e) {
            int line = e.getStackTrace()[0].getLineNumber();
            System.out.println("threw " + e + " at line #" + line);
            threwException = true;
        }

        String text1 = text(p, "p");
        String text2 = text(q, "q");
        int correct = 0;
        int nulls = 0;

        System.out.println("after:");
        if (text1.equals(answer1)) {
            correct++;
            System.out.println("  " + text1);
        } else {
            System.out.println("  " + text1 + " (should be " + answer1 + ")");
            if (text1.startsWith(answer1)) {
                nulls++;
            }
        }
        if (text2.equals(answer2)) {
            correct++;
            System.out.println("  " + text2);
        } else {
            System.out.println("  " + text2 + " (should be " + answer2 + ")");
            if (text2.startsWith(answer2)) {
                nulls++;
            }
        }
            
        if (correct == 2 && !threwException) {
            System.out.println("PASS");
            passCount++;
        } else if (correct + nulls == 2) {
            System.out.print("PARTIAL PASS");
            if (nulls > 0) {
                System.out.print(" with " + nulls + " null assignment(s)");
            }
            if (threwException) {
                System.out.print(" eliminating exception code");
            }
            System.out.println();
        } else {
            System.out.println("FAILED");
        }
        System.out.println();
    }

    public static String text(ListNode p, String text) {
        String result = text;
        for (int i = 0; i < 5; i++) {
            if (p != null) {
                result += "->[" + p.data + "]";
                p = p.next;
            }
        }
        if (p != null) {
            result += "...";
        }
        return result;
    }
}

class ListNode {
    public int data;       // data stored in this node
    public ListNode next;  // link to next node in the list

    // post: constructs a node with data 0 and null link
    public ListNode() {
        this(0, null);
    }

    // post: constructs a node with given data and null link
    public ListNode(int data) {
        this(data, null);
    }

    // post: constructs a node with given data and given link
    public ListNode(int data, ListNode next) {
        this.data = data;
        this.next = next;
    }
}