[Hackerrank] Pairs

https://www.hackerrank.com/challenges/pairs/problem

1) 코드

#!/bin/python3

import math
import os
import random
import re
import sys

#
# Complete the 'pairs' function below.
#
# The function is expected to return an INTEGER.
# The function accepts following parameters:
#  1. INTEGER k
#  2. INTEGER_ARRAY arr
#

def pairs(k, arr):
    arrSet = set()
    answerSet = set()
    for num in arr:
        arrSet.add(num)

    for num in arr:
        if num + k in arrSet:
            answerSet.add(str(num) + str(num+k))
        elif num - k in arrSet:
            answerSet.add(str(num-k) + str(num))
    
    return len(answerSet)



if __name__ == '__main__':
    fptr = open(os.environ['OUTPUT_PATH'], 'w')

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

    n = int(first_multiple_input[0])

    k = int(first_multiple_input[1])

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

    result = pairs(k, arr)

    fptr.write(str(result) + '\n')

    fptr.close()

2) 해설