I have this assignement problem:
There are three machines to perform four tasks. The costs of assigning to a machine each of the tasks are given by the following matrix:
$$\begin{pmatrix} 2 & 6 & 4 & 4\\ 3&4&4&3\\ 2&5&6&5 \end{pmatrix}$$ $a)$ Determine an optimal assignement assuming that each machine must perform exactly one task and therefore, one of the tasks will not be performed.
$b)$ determine an optimal assigement assuming that each machine can perform at the most two tasks and that every task must be performed.
So far, the assignement problems I've been asked to solve have a square matrix as the cost matrix, and each agent was required to perform exactly one task in a way that all tasks were performed and I would use the Hungarian algorithm to solve them. However, the algorithm works only for $n \times n$ matrix and I don't know how to proceed. So my question is:
How do I transform this problem so I can use the Hungarian Algorithm to solve it?
Thanks in advance.