// Program to test solutions to problem #3 on the cse143 midterm, spring 2011.
// Fill in your solution to minGap, then compile and run the program

import java.util.*;

class LinkedIntList {
    public int minGap() {
        // fill in your solution here
    }

    private ListNode front;  // first value in the list

    // this is the sample solution
    public int minGap2() {
        if (front == null || front.next == null) {
            return 0;
        } else {
            int min = front.next.data - front.data;
            ListNode current = front.next;
            while (current.next != null) {
                int gap = current.next.data - current.data;
                if (gap < min) {
                    min = gap;
                }
                current = current.next;
            }
            return min;
        }
    }

    // post: constructs an empty list
    public LinkedIntList() {
        front = null;
    }

    // post: creates a comma-separated, bracketed version of the list
    public String toString() {
        if (front == null)
            return "[]";
        else {
            String result = "[" + front.data;
            ListNode current = front.next;
            while (current != null) {
                result += ", " + current.data;
                current = current.next;
            }
            result += "]";
            return result;
        }
    }

    // post: appends the given value to the end of the list
    public void add(int value) {
        if (front == null)
            front = new ListNode(value);
        else {
            ListNode current = front;
            while (current.next != null)
                current = current.next;
            current.next = new ListNode(value);
        }
    }
}

public class Test3 {
    public static void main(String[] args) {
        test(new int[] {});
        test(new int[] {42});
        test(new int[] {3, 3, 3});
        test(new int[] {4, 5});
        test(new int[] {0, 10, 15, 23, 45});
        test(new int[] {1, 2, 2, 3, 3, 3});
        test(new int[] {-8, -5, -5, 0, 17});
        test(new int[] {42, 42, 42, 42, 42});
        test(new int[] {1, 3, 6, 7, 12});
        test(new int[] {3, 5, 11, 4, 8});
        test(new int[] {5, 105, 206, 308, 411, 515, 620});
        test(new int[] {-5, -105, -206, -308, -411, -515, -620});
        test(new int[] {0, Integer.MAX_VALUE});
    }

    public static void test(int[] data) {
        LinkedIntList list = new LinkedIntList();
        for (int n : data) {
            list.add(n);
        }
        System.out.println("list   = " + list);
        int gap1 = list.minGap2();
        System.out.println("minGap = " + gap1);
        boolean fail = false;
        try {
            int gap2 = list.minGap();
            if (gap1 != gap2) {
                fail = true;
                System.out.println("yours  = " + gap2);
            }
        } catch (RuntimeException e) {
            System.out.println("    threw " + e);
            fail = true;
        }
        if (fail)
            System.out.println("failed");
        else
            System.out.println("passed");
        System.out.println();
    }
}

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;
    }
}