topological-sort

问题 lst = [(u'course', u'session'), (u'instructor', u'session'), (u'session', u'trainee'), (u'person', u'trainee'), (u'person', u'instructor'), (u'course', u'instructor')] I've above list of tuple, I need to sort it with following logic.... each tuple's 2nd element is dependent on 1st element, e.g. (course, session) -> session is dependent on course and so on.. I want a sorted list based on priority of their dependency, less or independent object will come first so output should be like below,

问题 lst = [(u'course', u'session'), (u'instructor', u'session'), (u'session', u'trainee'), (u'person', u'trainee'), (u'person', u'instructor'), (u'course', u'instructor')] I've above list of tuple, I need to sort it with following logic.... each tuple's 2nd element is dependent on 1st element, e.g. (course, session) -> session is dependent on course and so on.. I want a sorted list based on priority of their dependency, less or independent object will come first so output should be like below,

问题 lst = [(u'course', u'session'), (u'instructor', u'session'), (u'session', u'trainee'), (u'person', u'trainee'), (u'person', u'instructor'), (u'course', u'instructor')] I've above list of tuple, I need to sort it with following logic.... each tuple's 2nd element is dependent on 1st element, e.g. (course, session) -> session is dependent on course and so on.. I want a sorted list based on priority of their dependency, less or independent object will come first so output should be like below,

来源： https://stackoverflow.com/questions/63347900/how-to-do-a-topological-sort-from-a-subset-of-items-from-a-given-graph

问题 So I got 4 rectangular shapes and I'm trying to apply a sorting algorithm (painters algorithm) to know which shapes (in 3d) I need to draw first and which one after. Note : The camera is in the bottom right corner: The correct order would be: purple, red, blue, green (for drawing of course reversed order). So I've implemented an algorithm which creates something like this: Theres every object listed with it's correct successors and predecessors . ITEM: red predecessor: - successor: - ITEM:

问题 Probably best illustrated with a small example. Given the relations A < B < C A < P < Q Correct outputs would be ABCPQ or APQBC or APBCQ ... etc. In other words, any ordering is valid in which the given relationships hold. I am most interested in the solution that is easiest to implement, but the best O(n) in speed and time is interesting as well. 回答1: This is called topological sorting. The standard algorithm is to output a minimal element, then remove it and repeat until done. 回答2: Do

问题 Probably best illustrated with a small example. Given the relations A < B < C A < P < Q Correct outputs would be ABCPQ or APQBC or APBCQ ... etc. In other words, any ordering is valid in which the given relationships hold. I am most interested in the solution that is easiest to implement, but the best O(n) in speed and time is interesting as well. 回答1: This is called topological sorting. The standard algorithm is to output a minimal element, then remove it and repeat until done. 回答2: Do

问题 Does anyone know of a random algorithm for generating a topological sort of a DAG, where each invocation of the algorithm has a non-zero probability of generating every valid topological sort of the DAG. It's crucial that the algorithm does not preclude any valid topological sort, because it's part of a larger algorithm that, given enough iterations, must be demonstrably capable of exploring all topological sorts of a given DAG. Does anyone know if such an algorithm has been developed?

问题 I'm trying to work out if my problem is solvable using the builtin sorted() function or if I need to do myself - old school using cmp would have been relatively easy. My data-set looks like: x = [ ('business', Set('fleet','address')) ('device', Set('business','model','status','pack')) ('txn', Set('device','business','operator')) .... The sort rule should be basically for all value of N & Y where Y > N, x[N][0] not in x[Y][1] Although I'm using Python 2.6 where the cmp argument is still

问题 I'm trying to create pseudo-code for an algorithm that will be able to determine whether a directed graph has a unique topological ordering. I've already come up with the following pseudo-code for a topological sort, but what would I have to add or edit in order to determine whether a digraph has a unique topological ordering? Input: A graph G Output: A list L that contain the sorted vertices define an empty list L; create a stack Stack; push all vertices with no incoming edges into Stack;