我正在尝试使用 MergeSort 从文件中计算反转,我的代码似乎适用于较小的文件,但较大的文件会产生错误的输出。我的代码:
反转计数.py:
count = 0
def merge_sort_inversions(numberlist):
if len(numberlist) < 2:
return numberlist
else:
mid = len(numberlist) // 2
lefthalf = numberlist[:mid]
righthalf = numberlist[mid:]
return sort_count_inversions(merge_sort_inversions(lefthalf), merge_sort_inversions(righthalf))
def sort_count_inversions(l, r):
result = []
i=0
j=0
global count
while(i < len(l) and j<len(r)):
if (r[j] > l[i]):
result.append(l[i])
i+= 1
elif(r[j] < l[i]):
result.append(r[j])
count += (len(l) - i)
j+=1
if(j>=len(r)):
result+=l
elif(i>=len(l)):
result+=r
print(count)
return result
应用程序.py:
import InversionCount
text_file = open('algorithms-1-test2.txt', 'r')
number_list = text_file.readlines()
number_list = list(map(int, number_list))
InversionCount.merge_sort_inversions(number_list)
答案是:2407905288,但我得到的最终打印计数是:22945388587258。我非常感谢任何帮助,因为我正在尝试自己学习算法。另外,我的问题发生在大文件上,那么我将如何调试似乎只有在输入非常大时才会出现的问题(我尝试用较小的输入对此进行测试,它给出了正确的答案)?谢谢!