Refactor algorithms and add some stuff

algorithms/geometry/convex_hull.cpp

algorithms/graph/articulations_bridges.cpp

algorithms/graph/bellman_ford.cpp

algorithms/graph/bfs.cpp

algorithms/graph/bipartite_match.cpp

algorithms/graph/dfs.cpp

algorithms/graph/dijkstra.cpp

algorithms/graph/dinic.cpp

algorithms/graph/edmonds_karp.cpp

algorithms/graph/floyd_warshall.cpp

algorithms/graph/ford_fulkerson.cpp

algorithms/graph/hopcroft_karp.cpp

algorithms/graph/kosaraju.cpp

algorithms/graph/kruskal.cpp

algorithms/graph/lca.cpp

algorithms/graph/prim.cpp

algorithms/graph/tarjan.cpp

algorithms/graph/topological_sort.cpp

algorithms/math/fft.cpp

algorithms/math/matrix.cpp