cycle

Explain how finding cycle start node in cycle linked list work?

由 断了今生、忘了曾经 提交于 2019-11-26 12:34:00
I understand that Tortoise and Hare's meeting concludes the existence of loop, but how does moving tortoise to beginning of linked list while keeping the hare at meeting place, followed by moving both one step at a time make them meet at starting point of cycle? This is Floyd's algorithm for cycle detection . You are asking about the second phase of the algorithm -- once you've found a node that's part of a cycle, how does one find the start of the cycle? In the first part of Floyd's algorithm, the hare moves two steps for every step of the tortoise. If the tortoise and hare ever meet, there

help in the Donalds B. Johnson's algorithm, i cannot understand the pseudo code (PART II)

由 拜拜、爱过 提交于 2019-11-26 12:31:35
问题 i cannot understand a certain part of the paper published by Donald Johnson about finding cycles (Circuits) in a graph. More specific i cannot understand what is the matrix Ak which is mentioned in the following line of the pseudo code : Ak:=adjacency structure of strong component K with least vertex in subgraph of G induced by {s,s+1,....n}; to make things worse some lines after is mentins \" for i in Vk do \" without declaring what the Vk is... As far i have understand we have the following

Cycles in family tree software

由 核能气质少年 提交于 2019-11-26 08:38:28
问题 I am the developer of some family tree software (written in C++ and Qt). I had no problems until one of my customers mailed me a bug report. The problem is that the customer has two children with their own daughter, and, as a result, he can\'t use my software because of errors. Those errors are the result of my various assertions and invariants about the family graph being processed (for example, after walking a cycle, the program states that X can\'t be both father and grandfather of Y). How

How many CPU cycles are needed for each assembly instruction?

由 江枫思渺然 提交于 2019-11-26 07:35:59
I heard there is Intel book online which describes the CPU cycles needed for a specific assembly instruction, but I can not find it out (after trying hard). Could anyone show me how to find CPU cycle please? Here is an example, in the below code, mov/lock is 1 CPU cycle, and xchg is 3 CPU cycles. // This part is Platform dependent! #ifdef WIN32 inline int CPP_SpinLock::TestAndSet(int* pTargetAddress, int nValue) { __asm { mov edx, dword ptr [pTargetAddress] mov eax, nValue lock xchg eax, dword ptr [edx] } // mov = 1 CPU cycle // lock = 1 CPU cycle // xchg = 3 CPU cycles } #endif // WIN32 BTW:

How to break outer cycle in Ruby?

由 怎甘沉沦 提交于 2019-11-26 07:28:07
问题 In Perl, there is an ability to break an outer cycle like this: AAA: for my $stuff (@otherstuff) { for my $foo (@bar) { last AAA if (somethingbad()); } } (syntax may be wrong), which uses a loop label to break the outer loop from inside the inner loop. Is there anything similar in Ruby? 回答1: What you want is non-local control-flow, which Ruby has several options for doing: Continuations, Exceptions, and throw / catch Continuations Pros: Continuations are the standard mechanism for non-local

Jackson - serialization of entities with birectional relationships (avoiding cycles)

由 心已入冬 提交于 2019-11-26 06:01:24
问题 I have two entities: Parent { Child[] children; } and Child { Parent parent; } I\'m aware about @JsonBackReference and @JsonManagedReference . They are good, if I\'m serializing instances of Parent . But I also need to transfer instances of Child and I want to have the parent field populated. In other words: On serialization of Parent it should have children but their parent field might be empty (can be solved by using json reference annotations). On serialization of Child it should have

How to determine if a linked list has a cycle using only two memory locations

由 …衆ロ難τιáo~ 提交于 2019-11-26 04:38:12
问题 Does anyone know of an algorithm to find if a linked list loops on itself using only two variables to traverse the list. Say you have a linked list of objects, it doesn\'t matter what type of object. I have a pointer to the head of the linked list in one variable and I am only given one other variable to traverse the list with. So my plan is to compare pointer values to see if any pointers are the same. The list is of finite size but may be huge. I can set both variable to the head and then

Explain how finding cycle start node in cycle linked list work?

由 …衆ロ難τιáo~ 提交于 2019-11-26 02:26:07
问题 I understand that Tortoise and Hare\'s meeting concludes the existence of loop, but how does moving tortoise to beginning of linked list while keeping the hare at meeting place, followed by moving both one step at a time make them meet at starting point of cycle? 回答1: This is Floyd's algorithm for cycle detection. You are asking about the second phase of the algorithm -- once you've found a node that's part of a cycle, how does one find the start of the cycle? In the first part of Floyd's

Finding all cycles in undirected graphs

由 筅森魡賤 提交于 2019-11-26 00:58:03
问题 I need a working algorithm for finding all simple cycles in an undirected graph. I know the cost can be exponential and the problem is NP-complete, but I am going to use it in a small graph (up to 20-30 vertices) and the cycles are small in number. After a long research (mainly here) I still don\'t have a working approach. Here is a summary of my search: Finding all cycles in an undirected graph Cycles in an Undirected Graph -> detects only whether there is a cycle or not Finding polygons

Finding all cycles in undirected graphs

由 天涯浪子 提交于 2019-11-26 00:27:56
I need a working algorithm for finding all simple cycles in an undirected graph. I know the cost can be exponential and the problem is NP-complete, but I am going to use it in a small graph (up to 20-30 vertices) and the cycles are small in number. After a long research (mainly here) I still don't have a working approach. Here is a summary of my search: Finding all cycles in an undirected graph Cycles in an Undirected Graph -> detects only whether there is a cycle or not Finding polygons within an undirected Graph -> very nice description, but no solution Finding all cycles in a directed graph
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