Write a simulation program of the lines at a grocery store.

Write a simulation program of the lines at a grocery store. Assume that there are 5 lines at the grocery. Customers enter randomly to check out, and then enter the shortest line. If the lines are equal, then the first available line is chosen. Each transaction takes a random amount of time to complete.

Additional features:

 Avoid a line if all lines are certain length.

 Leave a line if they have waited beyond a certain time.

 Switch lines if another line is shorter