Edexcel D1 2019 January — Question 1

Exam BoardEdexcel
ModuleD1 (Decision Mathematics 1)
Year2019
SessionJanuary
TopicMatchings and Allocation

  1. (a) Define the term 'bipartite graph'.
Six workers, \(\mathrm { A } , \mathrm { B } , \mathrm { C } , \mathrm { D } , \mathrm { E }\) and F , are to be matched to six tasks, 1, 2, 3, 4, 5 and 6 The table below shows the tasks that each worker is able to do.
WorkerTasks
\(A\)2,4
\(B\)5
\(C\)3,4
\(D\)2
\(E\)\(4,5,6\)
\(F\)1,6
(b) Using Diagram 1 in the answer book, draw a bipartite graph to show the possible allocation of workers to tasks.
(1) Initially, workers \(\mathrm { A } , \mathrm { C } , \mathrm { E }\) and F are allocated to tasks 2, 4, 5 and 6 respectively.
(c) Starting from the given initial matching, apply the maximum matching algorithm to obtain a complete matching. You must state the alternating paths that you use, and state your improved matching after each iteration.