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Unformatted text preview: Advanced Analysis of Algorithms  Homework IV (Solutions) K. Subramani LCSEE, West Virginia University, Morgantown, WV { ksmani@csee.wvu.edu } 1 Problems 1. Problem 26 . 2(9) on Page 664 of [CLRS01]. Solution: Let G = ( V,E ) denote the undirected graph and let s ∈ V denote an arbitrary vertex. Transform G into a flow network G ′ as follows: (i) Replace each undirected edge ( u,v ) ∈ E with two directed edges ( u,v ) and ( v,u ) , each with capacity 1 . (ii) Let s be the source vertex of the flow network. Run the maxflow algorithm treating each vertex u ∈ V − { s } as the sink t , recording the value of the maximum flow ( mf u ). The edgeconnectivity of G is then min u ∈ V −{ s } mf u . The crucial observation is that any cut of G , the vertex s is always on one side and hence it suffices to consider only the cases in which s is the source vertex in G ′ . It is straightforward to see that a directed cut in G ′ corresponds to a cut in G with the same capacity and vice versa. a50 2. Problem 26 . 3(3) on Page 668 of [CLRS01]. Solution: Without loss of generality, assume that  L  ≤  R  . Any augmenting path has the following structure: s → L → R →...
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This note was uploaded on 05/11/2010 for the course COMPUTER S 301 taught by Professor . during the Spring '10 term at Kadir Has Üniversitesi.
 Spring '10
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 Algorithms

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