Problem:

Queue

Queue is a container of elements that are inserted and deleted according to FIFO (First In First Out).

  For $n$ queues $Q_i$ ($i = 0, 1, ..., n-1$), perform a sequence of the following operations.

  
enqueue($t$, $x$): Insert an integer $x$ to $Q_t$.

  
front($t$): Report the value which should be deleted next from $Q_t$. If $Q_t$ is empty, do nothing.

  
dequeue($t$): Delete an element from $Q_t$. If $Q_t$ is empty, do nothing.

In the initial state, all queues are empty.

Input

  The input is given in the following format.

$n \; q$
$query_1$
$query_2$
:
$query_q$

Each query $query_i$ is given by

0 $t$ $x$

or

1 $t$

or

2 $t$

  where the first digits 0, 1 and 2 represent enqueue, front and dequeue operations respectively.

Output

  For each front operation, print an integer in a line.

Constraints

  
$1 \leq n \leq 1,000$

  
$1 \leq q \leq 200,000$

  
$-1,000,000,000 \leq x \leq 1,000,000,000$

Sample Input 1

3 9
0 0 1
0 0 2
0 0 3
0 2 4
0 2 5
1 0
1 2
2 0
1 0

Sample Output 1

1
4
2



Sample input:
3 9
0 0 1
0 0 2
0 0 3
0 2 4
0 2 5
1 0
1 2
2 0
1 0


Sample output:
1
4
2

Submission status: Accepted

Solution code:
from collections import deque


def main():
    num_queues, num_queries = [int(x) for x in input().split(" ")]
    qs = [deque() for i in range(num_queues)]
    for i in range(num_queries):
        query = input()
        if (query[0] == '0'):
            cmd, q_idx, elem = [int(x) for x in query.split(" ")]
            qs[q_idx].appendleft(elem)
        elif (query[0] == '1'):
            cmd, q_idx = [int(x) for x in query.split(" ")]
            if qs[q_idx]:
                print(qs[q_idx][-1])
        elif (query[0] == '2'):
            cmd, q_idx = [int(x) for x in query.split(" ")]
            if qs[q_idx]:
                qs[q_idx].pop()


if __name__ == '__main__':
    main()

Submission status: Accepted

Solution code:
from collections import deque
n, q = map(int, input().split())
Q = [deque() for _ in range(n)]
for _ in range(q):
    query = list(map(int, input().split()))
    if query[0] == 0:
        Q[query[1]].append(query[2])
    elif len(Q[query[1]]) > 0:
        if query[0] == 1:
            print(Q[query[1]][0])
        elif query[0] == 2:
            Q[query[1]].popleft()

Submission status: Accepted

Solution code:
from collections import deque
n, q = list(map(int, input().split()))
a = [deque([]) for i in range(n)]
for _ in range(q):
  q = list(map(int, input().split()))
  if q[0]==0:
    a[q[1]].append(q[2])
  elif q[0]==1:
    if len(a[q[1]])>0:
      print(a[q[1]][0])
  elif q[0]==2:
    if len(a[q[1]])>0:
      a[q[1]].popleft()

Submission status: Runtime Error

Solution code:
from collections import deque

a = [int(i) for i in input().split()]
q = deque([])
for i in range(a[0]): q.append(deque([]))

for i in range(a[1]):
    cmd = [int(i) for i in input().split()]

    if cmd[0] == 0:
        q[cmd[1]].append(cmd[2])

    elif cmd[0] == 1:
        if q[cmd[1]] != []: print(q[cmd[1]][0])

    elif cmd[0] == 2:
        if q[cmd[1]] != []: q[cmd[1]].popleft()