CODEWITHSUNDEEP
pythonrecursionreturn
asdasdasd
asdasdasd

Reputation: 1

Returning values from recusive function

This Code prints all Paths in a Graph from startNode to destinationNode. I copied it from https://www.geeksforgeeks.org/find-paths-given-source-destination/ and modified it slightly. The Code works perfectly fine, but i need the paths to be returned instead of printed, but don't get how to do that. If I add return to printAllPathsUtil(i, d, unvisited, path) it only returns one of the paths.

I am not that good at recursion and don't know what to do now.

async def getAllPathsUtil(s, d, unvisited, path): 
    unvisited.append(s)
    path.append(s) 
    if s == d: 
        path
    else: 
        for i in (await children(s)):
            if not(i in unvisited):
                await getAllPathsUtil(i, d, unvisited, path)
    path.pop() 
    unvisited.remove(s)

async def printAllPaths(startNode, destinationNode):
    all_paths = await getAllPathsUtil(startNode, destinationNode, [], [])
    print(all_paths)

Upvotes: 0

Views: 80

Answers (1)

Northern Poet
Northern Poet

Reputation: 2045

If you want to keep your recursive algorithm, than using yield might be the simplest option.

def graph_paths(s, d, visited, path): 
    visited.append(s)
    path.append(s) 
    if s == d: 
        yield path
    else: 
        for i in children(s):
            if i not in visited:
                yield from graph_paths(i, d, visited, path)

    path.pop() 
    visited.remove(s)

def print_graph_paths(start_node, dest_node):
  for path in graph_paths(start_node, dest_node, [], []):
    print(path)

But as a better approach I recommend to replace a recursion calls by the stack, it will neutralize the maximum recursion depth problem.

Upvotes: 1

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