diff --git a/sorts/topological_sort.py b/sorts/topological_sort.py index efce8165f..7613d07b2 100644 --- a/sorts/topological_sort.py +++ b/sorts/topological_sort.py @@ -1,10 +1,3 @@ -"""Topological Sort.""" - -# a -# / \ -# b c -# / \ -# d e edges: dict[str, list[str]] = { "a": ["c", "b"], "b": ["d", "e"], @@ -14,28 +7,16 @@ edges: dict[str, list[str]] = { } vertices: list[str] = ["a", "b", "c", "d", "e"] - def topological_sort(start: str, visited: list[str], sort: list[str]) -> list[str]: - """Perform topological sort on a directed acyclic graph.""" + visited.append(start) current = start - # add current to visited - visited.append(current) - neighbors = edges[current] - for neighbor in neighbors: - # if neighbor not in visited, visit + for neighbor in edges[start]: if neighbor not in visited: - sort = topological_sort(neighbor, visited, sort) - # if all neighbors visited add current to sort + topological_sort(neighbor, visited, sort) sort.append(current) - # if all vertices haven't been visited select a new one to visit - if len(visited) != len(vertices): - for vertice in vertices: - if vertice not in visited: - sort = topological_sort(vertice, visited, sort) - # return sort return sort - if __name__ == "__main__": sort = topological_sort("a", [], []) + sort.reverse() #Top down approach print(sort)