I used simple for loop to solve the 323 problem, and the result was wrong answer.
but i can't understand why it's wrong. testcase failed:

code below:
'''
class Solution:
def countComponents(self, n: int, edges: List[List[int]]) -> int:
connected = []
connected.append(edges[0])
for edge in edges[1:]:
for i in range(len(connected)):
if edge[0] in connected[i]:
if edge[1] in connected[i]:
pass
else:
connected[i].append(edge[1])
elif edge[1] in connected[i]:
if edge[0] in connected[i]:
pass
else:
connected[0].append(edge[0])
else:
connected.append(edge)

    return len(connected)
    

'''