There are n stationary cell-phones c1, ..., cn and n stationary cell-phone towers t1, ..., tn. The distances between cell-phones and towers are given to you in an n n matrix d, where d[i, j] denotes the distance between phone ci and tower tj .

It is possible for a cell-phone ci to connect to a tower tj if and only if the distance between ci and tj is at most D, where D is the connecting radius.

Furthermore, at one time, a cell-phone can connect to at most one tower and a tower can allow at most one connection.

Your job is to figure out whether all cell-phones are usable simultaneously.

That is, whether it is possible for all cell-phones to connect simultaneously to distinct towers.

Write a pseudocode for an algorithm that takes inputs n, D, and the distance matrix d, and outputs yes if it is possible for all cell-phones to simultaneously connect to distinct towers (within the connecting radius D) and no otherwise; and analyze running time.