Ford-Fulkerson algorithm for finding the maximum flow across a graph: https://en.wikipedia.org/wiki/Ford%E2%80%93Fulkerson_algorithm https://en.wikipedia.org/wi

Ford-Fulkerson algorithm for finding the maximum flow across a graph: https://en.wikipedia.org/wiki/Ford%E2%80%93Fulkerson_algorithm https://en.wikipedia.org/wiki/Ford%E2%80%93Fulkerson_algorit... The algorithm itself is interesting enough, but when applied to bipartite graphs, you can solve some tough problems very efficiently. For instance, one of my favorites is how Santa could possibly match a million kids with a million different gifts in order to maximize happiness. It turns out you structure the problem as a bipartite graph with nodes on one side for gifts and children on the other, and Ford-Fulkerson can guarantee the best matching in polynomial time (no small feat, given how many possible combinations there are!)