Python Question

Using Greedy Activity Selector

Activity Selection Last-to-Start Implementation

Need help implementing a python3 program

Using an input file named input.txt. Implement the activity selection last-to-start algorithm described in this problem. Display results to the screen. Using Python 3.

CLRS 16-1-2 Activity Selection Last-to-Start Suppose that instead of always selecting the first activity to finish, we instead select the last activity to start that is compatible will all previously selected activities. The program should read input from a file named input.txt. The file contains lists of activity sets with number of activities in the set in the first line followed by lines containing the activity number, start time & finish time.

Example input.txt:

11

1 1 4

2 3 5

3 0 6

4 5 7

5 3 9

6 5 9

7 6 10

8 8 11

9 8 12

10 2 14

11 12 16

3

3 6 8

1 7 9

2 1 2

In the above example the first activity set contains 11 activities with activity 1 starting at time 1 and finishing at time 4, activity 2 starting at time 3 and finishing at time 5, etc.. The second activity set contains 3 activities with activity 3 starting at time 6 and finishing at time 8 etc. The activities in the file are not in any sorted order.

Your results including the number of activities selected and their order should be outputted to the terminal. For the above example the results are:

Set 1 Number of activities selected = 4 Activities: 2 4 9 11 Set 2 Number of activities selected = 2 Activities: 2 1

Note: There is an alternative optimal solution for Set 1. Since activities 8 and 9 have the same start time of 8, a2 a4 a8 a11 would be an alternative solution. Your program only needs to find one of the optimal solutions. For either solution the activities differ from the solution presented in the text which uses the earliest-finish time criteria.