HackerRank 动态数组问题 - 代码中的运行时错误

Question

我正尝试在 HackerRank 上解决这个 Dynamic Array problem。这是我的代码：

#!/bin/python3

import math
import os
import random
import re
import sys

#
# Complete the 'dynamicArray' function below.
#
# The function is expected to return an INTEGER_ARRAY.
# The function accepts following parameters:
#  1. INTEGER n
#  2. 2D_INTEGER_ARRAY queries
#

def dynamicArray(n, queries):
    lastAnswer = 0
    a = []
    array_result = []
    for k in range(n):
        a.append([])
    
    for i in queries:
        x = i[1]
        y = i[2]
        if i[0] == 1:
            seq = ((x ^ lastAnswer) % n)
            a[seq].append(y)
        elif i[0] == 2:
            seq = ((x ^ lastAnswer) % n)
            lastAnswer = a[seq][y]
            array_result.append(lastAnswer)
    return array_result

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

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

    n = int(first_multiple_input[0])
    q = int(first_multiple_input[1])

    queries = [] # 1 0 5, 1 1 7, 1 0 3, ...

    for _ in range(q):
        queries.append(list(map(int, input().rstrip().split())))

    result = dynamicArray(n, queries)

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

    fptr.close()

我收到运行时错误：

Traceback (most recent call last):

File "Solution.py", line 50, in

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

TypeError: 'NoneType' object is not iterable

谁能帮我解决这个问题，我似乎找不到解决办法。

这是输入：

2 5

1 0 5

1 1 7

1 0 3

2 1 0

2 1 1

谢谢。

Update: It seems like this input is working now, thanks to @cireo but the code is not working for other test cases. What the problem with this code?

Answer 1

您的问题的答案在于 hackerrank 提供的样板。

# The function is expected to return an INTEGER_ARRAY.

您还可以看到 result = dynamicArray(n, queries) 需要 return 来自 map(str, result) 的整数列表，这会引发异常。

在你的代码中你做了 print(lastAnswer)，但你可能想要

+ ret = []
    ...
-     print(lastAnswer)
+     ret.append(lastAnswer)
+ return ret

相反。

因为你没有return任何东西，默认情况下函数returns None不能被map迭代。

Answer 2

你可以试试这个，它工作得很好。（没有运行时错误）

Replace your dynamicArray function with this code. Hopefully this will be helpful for you (^_^).

def dynamicArray(n, 查询):

col = [[] for i in range(n)]
res = []
lastanswer = 0
for q in queries:
    data = (q[1]^lastanswer)%n
    if q[0] == 1:
        col[data].append(q[2])
    elif q[0] == 2:
        ind_x = q[2]%len(col[data])
        lastanswer = col[data][ind_x]
        res.append(lastanswer)
return res

HackerRank 动态数组问题 - 代码中的运行时错误

HackerRank Dynamic Array Problem - Runtime Error in the code

python

dynamic-arrays

data-structures

你可以试试这个，它工作得很好。（没有运行时错误）