greedy-algorithm

Greedy Algorithm

Approach to solve a problem by selecting the best option currently available

Selects the locally optimal choice at each step , hoping to acheive a global optimum

• Simple , easy to implement , fast

• Usually don’t provide globally optimum solution

• Never reconsiders its choices

Example

Find the maximum sum from root to node

Actual=27, Greedy=21 , Greedy lost as it picked 7 first ( locally optimum but not globally optimum)

Actual=27, Greedy=21 , Greedy lost as it picked 7 first ( locally optimum but not globally optimum)

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When to use?

2 conditions :

Greedy Choice Property

Choosing the best option at each step can lead to a global optimal solution

Optimal substructure

An optimal solution to the whole problem contains optimal solution to sub-problems

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