HackerRank Larry's Array - 競プロ

HackerRank Larry's Array

https://www.hackerrank.com/challenges/larrys-array/problem

提出

code: python

import math

import os

import random

import re

import sys

#

# Complete the 'larrysArray' function below.

#

# The function is expected to return a STRING.

# The function accepts INTEGER_ARRAY A as parameter.

#

def larrysArray(A):

# Write your code here

# Ai-1, Ai, Ai+1 = Ai, Ai+1, Ai-1

if __name__ == '__main__':

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

t = int(input().strip())

for t_itr in range(t):

n = int(input().strip())

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

result = larrysArray(A)

fptr.write(result + '\n')

fptr.close()

解説

code: python

import math

import os

import random

import re

import sys

#

# Complete the 'larrysArray' function below.

#

# The function is expected to return a STRING.

# The function accepts INTEGER_ARRAY A as parameter.

#

def larrysArray(A):

# Write your code here

s = 0

# calculate number of inversions

# 1,6,5,2,4,3 -> 0 + 4 + 3 + 0 + 1 + 0

# 1 3 4 2 -> 0 + 1 + 1 + 0

# 1 2 3 5 4 -> 0 + 0 + 0 + 1 + 0

for i in range(n):

for j in range(i+1, n):

if Ai > Aj:

s += 1

if s%2 == 0:

return "YES"

else:

return "NO"

if __name__ == '__main__':

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

t = int(input().strip())

for t_itr in range(t):

n = int(input().strip())

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

result = larrysArray(A)

fptr.write(result + '\n')

fptr.close()

メモ

https://www.youtube.com/watch?v=Fq88svB99MA