find_union_algo created by bityob - https://repl.it/J8x7/7

find_union_algo.py

indata = """1 2
3 4
5 6
7 8
7 9
2 8
0 6
1 9"""

data = [x.split() for x in indata.splitlines()]

connections = []

def add_conn(newconn):
  isexists = False
  
  for conn in connections:
    if any(x in conn for x in newconn):
      conn.add(newconn[0])
      conn.add(newconn[1])
      isexists = True
  
  for conn1 in connections:
    for conn2 in connections:
      if (conn1 != conn2) and len(conn1 & conn2) > 0:
        connections.append(conn1 | conn2)
        connections.remove(conn1)
        connections.remove(conn2)
    
  if not isexists:
    connections.append(set(newconn))
    
  print(f"\t{connections}")
    
for newconn in data:
  print(newconn)
  add_conn(newconn)

print(connections) #[{'4', '3'}, {'6', '5', '0'}, {'8', '7', '1', '2', '9'}]

# output:
# ['1', '2']
# 	[{'2', '1'}]
# ['3', '4']
# 	[{'2', '1'}, {'4', '3'}]
# ['5', '6']
# 	[{'2', '1'}, {'4', '3'}, {'6', '5'}]
# ['7', '8']
# 	[{'2', '1'}, {'4', '3'}, {'6', '5'}, {'8', '7'}]
# ['7', '9']
# 	[{'2', '1'}, {'4', '3'}, {'6', '5'}, {'9', '8', '7'}]
# ['2', '8']
# 	[{'4', '3'}, {'6', '5'}, {'8', '7', '1', '2', '9'}]
# ['0', '6']
# 	[{'4', '3'}, {'6', '5', '0'}, {'8', '7', '1', '2', '9'}]
# ['1', '9']
# 	[{'4', '3'}, {'6', '5', '0'}, {'8', '7', '1', '2', '9'}]