Pushzerostoend.py

# You have been given a random integer array/list(ARR) of size N. You have been required to push all the zeros that are present in the array/list to the end of it. Also, make sure to maintain the relative order of the non-zero elements.

# Input format :
# The first line contains an Integer 't' which denotes the number of test cases or queries to be run. Then the test cases follow.
# First line of each test case or query contains an integer 'N' representing the size of the array/list.
# Second line contains 'N' single space separated integers representing the elements in the array/list.

from sys import stdin

def pushZerosAtEnd(arr, n) :
    #Your code goes here
    nonZero = 0
    for i in range(n):
        if arr[i] != 0:
            arr[i], arr[nonZero] = arr[nonZero], arr[i]
            nonZero += 1
    return arr


#Taking Input Using Fast I/O
def takeInput() :
    n = int(stdin.readline().rstrip())

    if n == 0:
        return list(), 0
    
    arr = list(map(int, stdin.readline().rstrip().split()))
    return arr, n
  

#to print the array/list
def printList(arr, n) : 
    for i in range(n) :
        print(arr[i], end = " ")

    print()


#main
t = int(stdin.readline().strip())

while t > 0 :

    arr, n = takeInput()

    pushZerosAtEnd(arr, n)
    printList(arr, n)

    t -= 1