HW$1$: VBA IN MS EXCEL $-$

A GREEDY ALGORITHM FOR SCHEDULING PROBLEM

You are going to use "Greedy.xlsm$"$ workbook for homework which requires a greedy

algorithm to solve a scheduling problem. You need to assign tasks to existing workstations

using a greedy algorithm as described below.

A Greedy Algorithm for Scheduling Problem

Having $n$ tasks to be assigned to $m$ workstations, a simple Greedy algorithm selects the

unassigned task with the maximum processing time at each step and assigns it to the

workstation with the smallest total processing time.

An example is given below:

Suppose we have $9$ tasks with the following processing times: $3,5,6,10,11,14,15,18,$ and

$20$ minutes.

And suppose we have $3$ workstations on which these tasks can be processed.

At each step, the algorithm selects the unassigned task with the maximum processing time

and assigns it to the workstation with the least total processing time.

The result is as follows:

S$2$

$18$

$11$

$6$

S$3$

$15$

$14$

$5$

The algorithm makes $9$ choices and finds the solution in $9$ iterations. You can check how the

algorithm works manually.

ASSIGNMENT

You are expected to create a sub procedure that runs the Greedy Algorithm to assign $26$

tasks $($with no precedence relation$)$ to the two available stations $($A and B$).$

In the Assignment sheet of the attached file Greedy.xlsm$,$ you will see a table containing the

following columns:

Department of Industrial Engineering, Middle East Technical University

IE $304$: Production and Service Information Systems

HW $1$: VBA IN MS EXCEL $-$ SOLVING A SINGLE$-$ROW LAYOUT

Tasks: the task names are listed in this column. We have tasks from T$1$ to T$26.$

Task Times: Processing times of the tasks are displayed in this column. Given task

times are just random integers $($you may change them for testing your code$).$

Due time: Shows the due time of the corresponding task assuming that you are

currently at time zero.

Assigned Station: Initially, this column is empty. Your code is expected to:

o type A for the tasks that are assigned to the first station.

o type B for the tasks that are assigned to the second station.

Order in Station: Initially, this column is also empty. Your code is expected to type

the order of the task in the station that it is assigned to$.$

Status: For each task in the list, show the status $($Finished in time, finished late,

in$-$process or waiting$)$ at the time given next to cell Current Time $($cell K$5).$

Finishing Time: The time when the task is finished. Leave blank if it is not finished

yet at the time given next to cell Current Time $($cell K$5).$

Macro $1$: Create a macro that carries out the algorithm defined in $1\mathrm{.}1.$ Assign your macro to

Assign Tasks button in Assignment sheet.

Macro $2$: Create another macro that gives the Status and Finishing Time information.

Assign this macro to View Status button. This macro should also display the machine status

indicating the current task in process and the next task to be processed for each machine in

cells K$13$:L$14.$