Data Structures and Algorithms in Java[1].pdf - Fulvio Frisone

there is no swap needed, and returns back to the outer loop. That is, we perform
only one iteration of the inner loop for each iteration of the outer loop. Thus, in
this case, we perform a minimum number of comparisons. Of course, we might
have to do a lot more work than this if the input array is extremely out of order. In
fact, we will have to do the most work if the input array is in decreasing order.
3.1.3 java.util Methods for Arrays and Random Numbers
Because arrays are so important, Java provides a number of built-in methods for
performing common tasks on arrays. These methods appear as static methods in the
java.util.Arrays class. That is, they are associated with the class,
java.util.Arrays itself, and not with a particular instance of this class.
Describing some of these methods will have to wait, however, until later in this
book (when we discuss the concept that these methods are based on).
Some Simple Methods of java.util.Arrays
We list below some simple methods of class java.util.Arrays that need no
further explanation:
equals(A, B): Returns true if and only if the array A and the array B
are equal. Two arrays are considered equal if they have the same number of
elements and every corresponding pair of elements in the two arrays are equal.
That is, A and B have the same elements in the same order.
fill(A,x): Stores element x into every cell of array A.
elements.
sort(A): Sorts the array A using the natural ordering of its
toString(A): Returns a String representation of the array A.
For example, the following string would be returned by the method toString
called on an array of integers A = [4,5,2,3,5,7,10]:
[4, 5, 2, 3, 5, 7, 10]
Note that, from the list above, Java has a built-in sorting algorithm. This is not the
insertion-sort algorithm we presented above, however. It is an algorithm called
quick-sort, which usually runs much faster than insertion—sort. We discuss the
quick-sort algorithm in Section 11.2.
An Example Using Pseudo-Random Numbers
153