Suppose we have n programs p$1,...,$pn to be executed. The programs are described in an

input text file that looks like the left column below with descriptions on the right:

n n is the number of programs.

path$\_1$ The subsequent n lines contain the fully qualified

$.$ paths of the programs to be executed $($ordered

$..$

path$\_$n

from $1$ to n$).$

Figure $1$: Sample input file

$($a$)$ Suppose the programs are independent from each other, so that they can be executed in

parallel. Write a parallel program executor, receiving the absolute path of the above$-$

mentioned input file as a command$-$line argument. This program runs all the programs listed

in the file in parallel.

$($b$)$ Now suppose each program pi depends on all the programs p$1,...,$pi$1.$ This means the

programs should be executed sequentially, first completing p$1,$ then p$2$ and so on$.$ Modify the

parallel program executor you designed in part $($a$)$ to obtain a sequential program executor