Building Teams

# def team_formation(no_students):

#     for _ in range(w):
#         team1,team2 = [int(x) for x in input().split()]
#         team1.append(w[0])
#         team2.append(w[1])

# def separate_into_teams(students, friendships, num_teams):
#     teams = {i: [] for i in range(num_teams)}
#     #friendships
#     friend_map = {student: set() for student in students}
#     for s1, s2 in friendships:
#         if s1 in friend_map and s2 in friend_map:
#             friend_map[s1].add(s2)
#             friend_map[s2].add(s1)
#     sorted_students = sorted(students, key=lambda s: len(friend_map[s]), reverse=True)
    
#     for student in sorted_students:
#         placed = False
#         sorted_team_ids = sorted(teams.keys(), key=lambda t_id: len(teams[t_id]))
        
#         for team_id in sorted_team_ids:
#             #if friend in this team?
#             if not any(friend in teams[team_id] for friend in friend_map[student]):
#                 teams[team_id].append(student)
#                 placed = True
#                 break
                
#         if not placed:
#             smallest_team = min(teams.keys(), key=lambda t_id: len(teams[t_id]))
#             teams[smallest_team].append(student)
            
#     return teams

# assigned_teams = separate_into_teams(pupils, friendships, number_of_teams)
# for team_num, members in assigned_teams.items():
#     print(f"Team {team_num + 1}: {', '.join(members)}")



import sys
from collections import deque

def solve_teams():
    input_data = sys.stdin.read().split()
    if not input_data:
        return

    n = int(input_data[0])
    m = int(input_data[1])

    graph = {i: [] for i in range(1, n + 1)}
    idx = 2
    for _ in range(m):
        u = int(input_data[idx])
        v = int(input_data[idx+1])
        graph[u].append(v)
        graph[v].append(u)
        idx += 2
#initially 0 then assigned
    team_assignment = [0] * (n + 1)

    for pupil in range(1, n + 1):
        if team_assignment[pupil] == 0:
            team_assignment[pupil] = 1
            queue = deque([pupil])

            while queue:
                current = queue.popleft()
                current_team = team_assignment[current]
                #friend in ooposite
                opposite_team = 2 if current_team == 1 else 1

                for friend in graph[current]:
                    if team_assignment[friend] == 0:
                        team_assignment[friend] = opposite_team
                        queue.append(friend)
                    elif team_assignment[friend] == current_team:
                        print("IMPOSSIBLE")
                        return

    team_1 = [str(i) for i in range(1, n + 1) if team_assignment[i] == 1]
    team_2 = [str(i) for i in range(1, n + 1) if team_assignment[i] == 2]

    print(f"Team 1: {', '.join(team_1)}")
    print(f"Team 2: {', '.join(team_2)}")

if __name__ == "__main__":
    solve_teams()

Test 1

Verdict: WRONG ANSWER

Test 2

Verdict: WRONG ANSWER

Test 3

Verdict: WRONG ANSWER

Test 4

Verdict: WRONG ANSWER

Test 5

Verdict: ACCEPTED

Test 6

Verdict: WRONG ANSWER

Test 7

Verdict: WRONG ANSWER

Test 8

Verdict: WRONG ANSWER

Test 9

Verdict: WRONG ANSWER

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED