weighted graphs bordo colina ajo flor figure danza erizo the minimum spanning tree send out the surveyors the algorithm for constructing the minimum spanning tree is little involvedso we're going to introduce it using an analogy involving cable tv employees you are one employee-- managerof course--and there are also various surveyors computer algorithm (unless perhaps it' neural networkdoesn' "knowabout all the data in given problem at onceit can' deal with the big picture it must acquire the data little by littlemodifying its view of things as it goes along with graphsalgorithms tend to start at some vertex and work outwardacquiring data about nearby vertices before finding out about vertices farther away we saw examples of this in the depth-first and breadth-first searches in the preceding in similar waywe're going to assume that you don' start out knowing the costs of installing the cable tv line between all the pairs of towns in magnaguena acquiring this information takes time that' where the surveyors come in starting in ajo you start by setting up an office in ajo (you could start in any townbut ajo has the best restaurants only two towns are reachable from ajobordo and danza (see figure you hire two toughjungle-savvy surveyors and send them out along the dangerous wilderness trailsone to bordo and one to danza their job is to determine the cost of installing cable along these routes the first surveyor arrives in bordohaving completed her surveyand calls you on her cell phoneshe says it will cost million dollars to install the cable link between ajo and bordo the second surveyorwho has had some trouble with crocodilesreports little later from danza that the ajo-danza linkwhich crosses more level countrywill cost only million dollars you make listajo-danza$ million ajo-bordo$ million