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isConsecutive

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Author: Stuart Reges (on 2014/02/13)

Write a method isConsecutive that returns true if a list of integers contains a sequence of consecutive integers and that returns false otherwise. Consecutive integers are integers that come one after the other, as in 5, 6, 7, 8, 9, etc. For example, if a variable called list stores these values: 

    [3, 4, 5, 6, 7, 8, 9, 10]

then the call: 

    list.isConsecutive()

should return true. If the list had instead contained this sequence: 

    [3, 4, 5, 6, 7, 8, 9, 10, 12]

then the call should return false because the numbers 10 and 12 are not consecutive. The following sequence of values would be consecutive except for the fact that it appears in reverse order, so the method would return false in this case: 

    [3, 2, 1]

Any list with fewer than two values should be considered to be consecutive.

You are writing a method for the ArrayIntList class discussed in lecture: 

    public class ArrayIntList {
        private int[] elementData; // list of integers
        private int size;          // current # of elements in the list

        <methods>
    }

You may not call any other methods of the ArrayIntList methods to solve this problem, you are not allowed to define any auxiliary data structures (no array, String, ArrayList, etc), and your solution must run in O(n) time.

Type your solution here:


This is a partial class problem. Submit code that will become part of an existing Java class as described. You do not need to write the complete class, just the portion described in the problem.

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