The assignment problem is a matching problem with n people and n jobs and a cost matrix with entry c$\_($ij$)$ representing the "cost" of assigning person i to job j$.$ The goal is a one$-$to$-$one matching of people to jobs that minimizes the sum of the costs. Set all diagonal entries in Figure $3\mathrm{.}13$ equal to $5$ and solve this $4$xx$4$ assignment problem by a branch$-$and$-$bound approach. How does an assignment problem differ from a traveling salesperson problem?