高效/可扩展的Python算法，用于查找多个元组列表的交集？

编程问答 2022-08-14

问题描述

我有多个包含元组的列表，例如

list_A = [(start_1,end_1),(start_2,end_2),(start_3,end_3)]
list_B = [(start_4,end_4),...]

是否有一种聪明的方法可以生成仅包含交点的result_list，而不必以嵌套的形式O（n ^ m）搜索每个列表？

示例：

list_A = [('8:00 AM','10:00 AM'),('12:59 PM','3:00 PM'),('5:04 PM','7:23 PM')]
list_B = [('9:06 AM','9:47 AM'),('9:51 AM','12:45 PM'),('1:33 PM','2:52 PM'),...]
list_C = [...]
list_D = [...]
# etc. etc. (m lists)

请查看下图以查看问题的说明：

Intersection Problem

解决方法

您可以在O（m * n）中执行以下操作-

r = [[1,3],[5,7],[9,11]]
s = [[2,4],6],[7,9],[11,14]]

r = [[i[0],i[1]+1] for i in r] #to make it inclusive at ends
s = [[i[0],i[1]+1] for i in s] #to make it inclusive at ends

overlapping_ranges = [set(range(*i[0])).intersection(set(range(*i[1]))) for i in list(itertools.product(r,s))]
overlapping_ranges = [i for i in overlapping_ranges if i] #removing nullsets

[{2,3},{5,6},{7},{9},{11}]
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