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Biologsts often construct a food network of species in an ecosystem. The vertice

ID: 3731407 • Letter: B

Question

Biologsts often construct a food network of species in an ecosystem. The vertices represent species, and a directed edge (u, v) means species u eats species v. Determine the effect of the extinction of a species. If a species v goes extinct, and there is some other species u that only eats v, then u will become extinct. This can cascade through the food network Given a food network and a species v, determine all other species that will become extinct if v goes extinct. Show pseudocode and work out the running time.

Explanation / Answer

Find_Ext(species v){

Danger_list +={All species eating species v}

foreach(Danger_list)

If(Selected species eats other species than species v)

{

remove from Danger_list

}

foreach(Danger_list)

{

Find(Selected species, food network) //recursion

}

}

The above pseudocode populates a list with Species that are directly or indirectly dependent on species v.

The running time will be n*n where n is total no of species in food network.