DFS recursive

dfs_recursive.py

# graph is represented by adjacency list: List[List[int]]
# s: start vertex
def dfs(graph, s):
    # set is used to mark visited vertices
    visited = set()

    def recur(current_vertex):
        print(current_vertex)

        # mark it visited
        visited.add(current_vertex)

        # Recur for all the vertices adjacent to current_vertex 
        for v in graph[current_vertex]:
            if v not in visited:
                recur(v)

    recur(s)