Write a program sort4x that splits an array into four parts, sorts each part on an image, then merges the four parts into the sorted array (use merge three times). Model it after the program sort2...

Write a program sort4x that splits an array into four parts, sorts each part on an

image, then merges the four parts into the sorted array (use merge three times).

Model it after the program sort2 (13.8). Make sure that the one-image version

does the same computation as the four-image version and compare the times.