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Unformatted text preview: 151/22Lesson 15: The Greedy MethodOptimization ProblemA problem in which some function (called the optimization or objective function) is to be optimized (usually minimized or maximized) subject to some constraints.152/22Feasible And Optimal SolutionsA feasible solution is a solution that satisfies the constraints.An optimal solution is a feasible solution that optimizes the objective/optimization function.153/22Greedy Method• Solve problem by making a sequence of decisions.• Decisions are made one by one in some order.• Each decision is made using a greedy criterion.• A decision, once made, is (usually) not changed later.• Greedy method gives a good heuristic.154/22Shortest Path Problems• Directed weighted graph.• Path length is sum of weights of edges on path.• The vertex at which the path begins is the source vertex.• The vertex at which the path ends is the destination vertex.155/22ExampleA path from 1 to 7.1234567261678103144453117Path length is 14.156/22ExampleAnother path from 1 to 7....
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This note was uploaded on 08/18/2011 for the course COMP 3868 taught by Professor Keithchan during the Summer '97 term at Hong Kong Polytechnic University.
 Summer '97
 KEITHCHAN

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