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

Solution in C (judge verdict: Accepted)

#include <stdio.h>

typedef struct node_t {
	int val;
	struct node_t *next;
} node;

node* new_node(int val) {
	static int it = 0;
	static node pool[200000];
	pool[it] = (node) { val, NULL };
	return &pool[it++];
}

node* st[1000];
node* en[1000];

int main(void)
{
	int n, q, com, t, x;
	node *tmp;
	scanf("%d%d", &n, &q);
	while (q--) {
		scanf("%d%d", &com, &t);
		if (com == 0) {
			scanf("%d", &x);
			tmp = new_node(x);
			if (!st[t]) st[t] = en[t] = tmp;
			else en[t]->next = tmp, en[t] = tmp;
		}
		else if (com == 1) {
			if (st[t]) printf("%d\n", st[t]->val);
		}
		else {
			if (st[t]) st[t] = st[t]->next;
		}
	}
	return 0;
}