When Greedy Algorithm Works?

A problem must comprise these two components for a greedy algorithm to work: It has optimal substructures. The optimal solution for the problem contains optimal solutions to the sub-problems. It has a greedy property (hard to prove its correctness!).

How does greedy algorithm work?

Greedy algorithms take all of the data in a particular problem, and then set a rule for which elements to add to the solution at each step of the algorithm. In the animation above, the set of data is all of the numbers in the graph, and the rule was to select the largest number available at each level of the graph.

How do you know if greedy algorithm is working?

One of the simplest methods for showing that a greedy algorithm is correct is to use a “greedy stays ahead” argument. This style of proof works by showing that, according to some measure, the greedy algorithm always is at least as far ahead as the optimal solution during each iteration of the algorithm.