Can you explain the greedy algorithms and when they are used?

Greedy algorithms make locally optimal decisions at each step with the hope that this will lead to a globally optimal result. They do not backtrack or consider all options, but choose the best option at the current moment.

Greedy algorithms are applied when the problem has the property of greediness — a local optimum leads to a global optimum. For example:

• Fractional knapsack problem
• Algorithms for finding the minimum spanning tree (Prim, Kruskal)
• Dijkstra's algorithm for shortest path (with non-negative weights)

Greedy algorithms are simple and efficient, but do not always provide an optimal solution for all problems.