I have a list of child-parent tuples. I would like to traverse through the tree to collect all the children for input node.
in_list = [(2,1),(3,2),(4,3),(6,5),(7,4),(8,4)]
Say now I would like to collect all children for node 2. That would be
out_list = [3,4,7,8]
Does this problem or its solution have any specific name? Just need to know where to look.
CodePudding user response:
You need to traverse these nodes in in_list
like DFS, You can try this:
def DFS(path, lst, father):
for (a,b) in lst:
if b == father:
path.append(a)
DFS(path, lst, a)
return path
in_list = [(2,1),(3,2),(4,3),(6,5),(7,4),(8,4)]
res = DFS([], in_list , 2)
print(res)
Output:
[3, 4, 7, 8]
CodePudding user response:
You can use a recursive generator function:
in_list = [(2,1),(3,2),(4,3),(6,5),(7,4),(8,4)]
def paths(n, c = []):
if not (t:=[a for a, b in in_list if b == n]):
yield from (c [n])
else:
yield from [j for k in t for j in paths(k, c [n])]
print([*set(paths(2))][1:])
Output:
[3, 4, 7, 8]