Python | Merge List with common elements in a List of Lists

# Python code to merge all sublist having common elements.

# Using recursion to merge all sublist having common elements.
def merge(Input, _start, _c = [], _seen = [], _used=[]):
    elem = [x for x in Input if any(y in _start for y in x) 
    and x not in _seen and x not in _used]
    if not elem:
        yield set(_c)
        for x in Input:
            if x != _start and x not in _used:
                yield from merge(Input, x, _c=[], _seen=[], 
                           _used=_used+[x, *elem])
    else:
        yield from merge(Input, _start, _c = _c + [x for
                                            y in elem for x in y],
                    _seen=_seen + elem, _used = _used + elem)

#Input list Initialization
Input = [[11, 27, 13], [11, 27, 55], [22, 0, 43],
         [22, 0, 96], [13, 27, 11], [13, 27, 55],
         [43, 0, 22], [43, 0, 96], [55, 27, 11]]

#Calling merge function
Output = list(map(list, {tuple(x) for
                         x in merge(Input, Input[0], _seen=[Input[0]])
                         if x}))

#Printing output
print("Initial list of list is :")
print(Input)
print("List of list after merging is:")
print(Output)

#Python code to merge all sublist having common elements.

#Importing 
from collections import defaultdict

#merge function to  merge all sublist having common elements.
def merge_common(lists):
    neigh = defaultdict(set)
    visited = set()
    for each in lists:
        for item in each:
            neigh[item].update(each)
    def comp(node, neigh = neigh, visited = visited, vis = visited.add):
        nodes = set([node])
        next_node = nodes.pop
        while nodes:
            node = next_node()
            vis(node)
            nodes |= neigh[node] - visited
            yield node
    for node in neigh:
        if node not in visited:
            yield sorted(comp(node))

#Input list initialization
Input = [['z','x','y'], ['y','g','e'], ['z'],['x','p'],
         ['a','b'], ['y','a'], ['d','g']]

#Calling merge function
Output = list(merge_common(Input))

#Printing function
print("Initial list of list is :")
print(Input)

print("List of list after merging is:")
print(Output)