Authors:
Stuart Reges, Marty Stepp
Chapter:
Arrays
Exercise:
Exercises
Question:15 | ISBN:9780136091813 | Edition: 2
Question
Write a method called collapse that accepts an array of integers as a parameter and returns a new array containing the result of replacing each pair of integers with the sum of that pair. For example, if an array called list stores the values {7, 2, 8, 9, 4, 13, 7, 1, 9, 10}, then the call of collapse(list) should return a new array containing {9, 17, 17, 8, 19}.
The first pair from the original list is collapsed into 9 (7 # 2), the second pair is collapsed into 17 (8 # 9), and so on. If the list stores an odd number of elements, the final element is not collapsed. For example, if the list had been {1, 2, 3, 4, 5}, then the call would return {3, 7, 5}. Your method should not change the array that is passed as a parameter.
Answer
Implementation of collapse method:
public static int[] collapse(int[] a)
{
int[] newArr = new int[(a.length + 1) / 2];
for(int i = 0, j = 0; i < a.length; i += 2, j++)
{
if(i + 1 < a.length)
{
newArr[j] = a[i] + a[i + 1];
}
else
{
newArr[j] = a[i];
}
}
return newArr;
}