Left Rotation in Python - HackerRank solution

Solution for hackerRank problem Left Rotation in Python

Problem :

A left rotation operation on an array of size n shifts each of the array's elements 1 unit to the left. Given an integer,d, rotate the array that many steps left and return the result.

Example

d = 2

arr = [1,2,3,4,5]

After 2 rotations, arr' = [3,4,5,1,2].

Function Description

Complete the rotateLeft function in the editor below.

rotateLeft has the following parameters:

• int d: the amount to rotate by
• int arr[n]: the array to rotate

Returns

• int[n]: the rotated array

Input Format

The first line contains two space-separated integers that denote n, the number of integers, and d, the number of left rotations to perform.

The second line contains n space-separated integers that describe arr[].

Constraints

• 1<=n<=10⁵
• 1<=d<=n
• 1<=a[i]<=10⁶

Sample Input

5 4

1 2 3 4 5

Sample Output

5 1 2 3 4

Explanation

To perform d=4 left rotations, the array undergoes the following sequence of changes:

[1,2,3,4,5] => [2,3,4,5,1] => [3,4,5,1,2] => [4,5,1,2,3] => [5,1,2,3,4]

Code :

#!/bin/python3

import math

import os

import random

import re

import sys

#

# Complete the 'rotateLeft' function below.

#

# The function is expected to return an INTEGER_ARRAY.

# The function accepts following parameters:

#  1. INTEGER d

#  2. INTEGER_ARRAY arr

#

def rotateLeft(d, arr):

    for i in range(d):

        p=arr.pop(arr.index(arr[0]))

        arr.append(p)

    return arr

if __name__ == '__main__':

    fptr = open(os.environ['OUTPUT_PATH'], 'w')

    first_multiple_input = input().rstrip().split()

    n = int(first_multiple_input[0])

    d = int(first_multiple_input[1])

    arr = list(map(int, input().rstrip().split()))

    result = rotateLeft(d, arr)

    fptr.write(' '.join(map(str, result)))

    fptr.write('\n')

    fptr.close()