[Algorithm] Hackerrank - Arrays: Left Rotation

문제:

A left rotation operation on an array shifts each of the array's elements 1 unit to the left. For example, if 2 left rotations are performed on array [1,2,3,4,5], then the array would become [3,4,5,1,2].

Given an array a of n integers and a number, d, perform d left rotations on the array. Return the updated array to be printed as a single line of space-separated integers.

Function Description

Complete the function rotLeft in the editor below. It should return the resulting array of integers.

rotLeft has the following parameter(s):

• An array of integers a.
• An integer d, the number of rotations.

Input Format

The first line contains two space-separated integers n and d, the size of a and the number of left rotations you must perform. 
The second line contains n space-separated integers a[i].

 

Output Format

Print a single line of  space-separated integers denoting the final state of the array after performing d left rotations.

Sample Input

5 4

1 2 3 4 5

Sample Output

5 1 2 3 4

Explanation

When we 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]

 

코드:

#!/bin/python3

import math
import os
import random
import re
import sys

# Complete the rotLeft function below.
def rotLeft(a, d):
    return a[d:] + a[:d]
if __name__ == '__main__':
    fptr = open(os.environ['OUTPUT_PATH'], 'w')

    nd = input().split()

    n = int(nd[0])

    d = int(nd[1])

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

    result = rotLeft(a, d)

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

    fptr.close()