prajwaldp / COP5536-Capstone-Priority-Scheduling-System

A priority scheduling system using a min heap and red-black-tree

UF Advanced Data Structures (COP5536) Capstone Project

Problem Description

A company is constructing many buildings and plan to use software to keep track of all buildings under construction in a new city.

A building record has the following fields:

• buildingNum: unique integer identifier for each building.

• executedTime: total number of days spent so far on this building.

• totalTime: the total number of days needed to complete the construction of

• the building.

The needed operations are:

1. Print(buildingNum) prints the triplet buildingNume, executedTime, totalTime.

2. Print(buildingNum1, buildingNum2) prints all triplets bn, executedTime, totalTime for which buildingNum1 <= bn <= buildingNum2.

3. Insert (buildingNum,totalTime) where buildingNum is different from existing building numbers and executedTime = 0.

In order to complete the given task, you must use a min-heap and a Red-Black Tree (RBT). Also, you may assume that the number of active buildings will not exceed 2000.

A min heap should be used to store (buildingNum, executedTime, totalTime) triplets ordered by executedTime. You will need a suitable mechanism to handle duplicate executedTimes in your min heap. An RBT should be used store (buildingNum, executedTime, totalTime) triplets ordered by buildingNum. You are required to maintain pointers between corresponding nodes in the min-heap and RBT.

The company works on one building at a time. When it is time to select a building to work on, the building with the lowest executedTime (ties are broken by selecting the building with the lowest buildingNum) is selected. The selected building is worked on until complete or for 5 days, whichever happens first. If the building completes during this period its number and day of completion is output and it is removed from the data structures. Otherwise, the building’s executedTime is updated. In both cases, The company selects the next building to work on using the selection rule. When no building remains, the completion date of the new city is output.

Instructions

1. Unzip the zipped archive, change directory to it and compile the java files into class files using the following command (on Linux)

$ make

2. Run the program using the following command

$ java risingCity [input-file.txt]

3. The output of the program is written to the file o​ utput_file.txt​. Use the following command to view the content of the output file.

$ cat output_file.txt 

Implementation Details

1. There are two counters for keeping track of passing days - d​ay​ keeps track of the days passed since the construction began and ​activeBuildingDay​ keeps track of the days passed since work began on the currently active building.

2. As buildings are introduced with passing days, they are inserted into the MinHeap.

3. If no building is being worked on, the building returned by the removeMin​ operation on the MinHeap is marked as the active building.

4. With every passing day, the ​executedTime​ of the building being worked on is incremented (both, the HeapNode’s and the RedBlackNode’s ​executedTime attribute is incremented).

5. When it‘s time for work to cease on the a​ ctiveBuilding​ (when it has been under construction for 5 days, with buildings in the queue), it is reinserted back into the MinHeap. The a​ ctiveBuildingDay​ counter is reset. The building that is then removed from the MinHeap (using the ​removeMin​ operation) becomes the activeBuilding. The removeMin operation returns the building with the least executed time (and building number, if the executed time is equal).

6. As buildings are inserted into the MinHeap (except, when the building is reinserted after being worked on), corresponding RedBlackNode objects are inserted into the RedBlackTree. When a building is completed, it is not reinserted back into the MinHeap and the corresponding RedBlackNode is deleted.

7. Since the RedBlackTree is a self-balancing binary search tree and contains all the buildings, it is used to retrieve buildings by the building number or in a range of building numbers efficiently.

Results

The repository contains the 7 java files and a sample input and outpute file.

$ java risingCity input_file.txt
$ cat output_file.txt
(15,1,200),(50,45,100)
(15,45,200),(50,45,100)
(15,47,200),(50,45,100)
(15,50,200),(30,0,50),(50,45,100)
(15,50,200),(30,1,50),(50,45,100)
(15,50,200),(30,5,50),(50,45,100)
(15,50,200),(30,40,50),(50,45,100)
(15,50,200),(30,45,50),(40,45,60),(50,45,100)
(15,50,200),(30,50,50),(40,45,60),(50,45,100)
(30,190)
(15,50,200),(40,50,60),(50,45,100)
(15,50,200),(40,50,60),(50,50,100)
(15,55,200),(40,54,60),(50,50,100)
(15,55,200),(40,55,60),(50,51,100)
(40,225)
(50,310)
(15,410)

LICENSE

This software is licensed under GNU GPLv3.