## Algorithm

Problem Name: Python - Collections.deque()

In this HackerRank Functions in PYTHON problem solution,

### collections.deque()

A deque is a double-ended queue. It can be used to add or remove elements from both ends.

Deques support thread safe, memory efficient appends and pops from either side of the deque with approximately the same 0(1) performance in either direction.

Example

Code

``````>>> from collections import deque
>>> d = deque()
>>> d.append(1)
>>> print d
deque()
>>> d.appendleft(2)
>>> print d
deque([2, 1])
>>> d.clear()
>>> print d
deque([])
>>> d.extend('1')
>>> print d
deque(['1'])
>>> d.extendleft('234')
>>> print d
deque(['4', '3', '2', '1'])
>>> d.count('1')
1
>>> d.pop()
'1'
>>> print d
deque(['4', '3', '2'])
>>> d.popleft()
'4'
>>> print d
deque(['3', '2'])
>>> d.extend('7896')
>>> print d
deque(['3', '2', '7', '8', '9', '6'])
>>> d.remove('2')
>>> print d
deque(['3', '7', '8', '9', '6'])
>>> d.reverse()
>>> print d
deque(['6', '9', '8', '7', '3'])
>>> d.rotate(3)
>>> print d
deque(['8', '7', '3', '6', '9'])
``````

Perform append, pop, popleft and appendleft methods on an empty deque d.

Input Format

The first line contains an integer N, the number of operations.
The next N lines contains the space separated names of methods and their values.

Constraints

0 < N <= 100

Output Format

Print the space separated elements of deque d.

Sample Input

``````6
append 1
append 2
append 3
appendleft 4
pop
popleft
``````

Sample Output

``````1 2
``````

## Code Examples

### #1 Code Example with Python Programming

```Code - Python Programming```

``````
from collections import deque

dq = deque()

for _ in range(int(input())):
name, *ele = input().split()
getattr(dq, name)(*ele)

print(*dq)
``````
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