# Questions tagged [hamiltonian-path]

Questions on Hamiltonian paths, that is, paths that visit each vertex exactly once in a graph.

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### Hamiltonian cycle in $C_n^k$ in polynomial time for constant $k$?

Let $C_n$ denote the cycle graph over $n$ vertices. Let $C_n^k$ denote the $k$-th power of the cycle graph, or namely that for two vertices $i,j$, $(i,j)\in Edges(C_n^k) \iff |i-j|\leq k$ for a ...
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### Seemingly simple path finding problem, but graph with travelling salesman or shortest path does not work

I am looking for an algorithm to a problem that I encountered when working with 3D modeling: On a 3D triangle surface mesh, I have multiple lines, some of them are open, some are closed. The are on ...
205 views

### Is this graph Hamiltonian?

My case is a directed graph with $n$ nodes with $(n-1)^2+1$ edges. I have done the following till now. We know that the maximum number of edges for a directed graph $K_n$ on $n$ nodes is $n(n-1)$ ...
96 views

### How to reduce the hamiltonian path problem to 1/2 hamiltonian path problem

Task: A Hamiltonian path of a graph is a path that visits all nodes of the graph exactly once. The hamiltion path problem (HPP) consists in deciding whether a given graph has such a path. Similarly, ...
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### Non-brute force algorithm for a Eulerian like path

I have a graph with an arbitrary amount of edges and vertexes. Each vertex having an arbitrary amount of edges connecting to it but in practice the number is usually around 3 or 4 no less than one ...
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### Prove the following claim on Hamilton Path?

I am trying to prove the following claim: Given DAG graph, there is Hamilton path iff the following algorithm returns true: Do topologic sorting. Move on the graph's vertices one by one (from low to ...
209 views

### find a path to visit every node in graph not necessarily once

I meet a problem but when I google, there are all Hamiltonian Path Problem: How to find a path to visit every node in directed graph(not necessarily once)? This problem is different from Hamiltonian ...
61 views

### If P = NP, do these NP-complete problems reduce to these specific easier versions?

I am trying to understand reductions and NP-completeness from Algorithms by Dasgupta et al. Chapter 8 has the table below and I am wondering: if $P = NP$ does each of the problems on the left reduce ...
37 views

### Given graph G and vertices v and w can you non-deterministically walk the "least Hamiltonian path" from v to w, if it exists?

My understanding of non-deterministic algorithms is that they're "as lucky as you want". ...you can think of the algorithm as being able to make a guess at any point it wants, and a space ...
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### Does this algorithm (least Hamiltonian path, checking vertex count, and no duplicates) decide Hamiltonian paths? If so, what is its space complexity?

Let G be a graph Suppose G has N vertices Let H be the ...
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### Proving NP-hardness of Hamiltonian Cycle problem variant

I need to prove that determining whether a graph has a relaxed-Hamiltonian cycle (definition given ahead) is NP-hard. A relaxed-Hamiltonian cycle in $G$ is a closed walk $C$ that visits every vertex ...
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### Is reduction from Rudrata/Hamiltonian path to Rudrata/Hamiltonian cycle O(1)?

I am reading about P and NP and looking at the reduction of a Rudrata/Hamiltonian path to a Rudrata cycle. I think adding an extra node and 2 edges connecting the start, ...
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### Is O(1) considered polynomial time?

I am reading about P and NP and looking at the reduction of a Rudrata/Hamiltonian path to a Rudrata cycle. I think adding an extra node and 2 edges connecting the start, ...
32 views

### Number of Hamilton paths in graphs

I am trying to find a fast algorithm that can compute the number of hamiltonian paths in an undirected graph. I saw this on the web, but it sounds like this finds all hamiltonian paths starting from ...
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### If there is no Hamiltonian path in a DAG then there are at least two different Topological sorts

I understand the concept that if there is no Hamiltonian path so there will be 2 smaller paths and with them I can build more then one topological sort but I am not sure how make it formal. Can you ...
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### Examples of difficult Hamiltonian Cycle Problems

I am working on implementing algorithms to solve Hamiltonian Cycle Problem. I need difficult problem graphs to test my implementations but my google-fu is weak and am unable to find any. Please advise ...
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### What is the polynomial time reduction between these two Hamiltonian cycle problems?

Problem 1: Given an undirected graph, return the edges of a Hamiltonian cycle, or correctly decide that the graph has no such cycle. Problem 2: Given an undirected graph, decide whether or not the ...
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### Confusion in Reduction of Hamiltonian-Path to Hamiltonian-Cycle

The following is an excerpt from a material on NP-Theory: "Let G be an undirected graph and let s and t be vertices in G. A Hamiltonian path in G is a path from s to t using edges of G, on which ...
397 views

### Diameter of a disconnected graph

Given G(V,E) a graph that has 2 connected components, what is the diamter of this graph?
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### What is an example of a Monte-Carlo algorithm for finding a Hamiltonian path?

I've recently been made aware that there exist Monte-Carlo algorithm(s?) for determining whether a Hamiltonian path exists in a graph. I am struggling to figure out how it would work. What is the ...
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### Does this imply Hamiltonian path cannot be decided in nondeterministic logspace?

Suppose I nondeterministically walk around in a graph with n vertices. When looking for a Hamiltonian path, at some point I’ve walked n/2 vertices. There are (n choose n/2) different combinations of ...
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### Does this imply checking a candidate Hamiltonian Path solution can be done in logspace?

Assume vertices are integers base 2. Smallest vertex is 1. There are n vertices. Our input is: the number of vertices (n expressed in log(n) bits - ...
51 views

### Finding a hamiltonianISH path in a graph

Problem statement Given a graph of all the blue squares in the following image where each blue square is connected to other blue squares in all 4 cardinal directions. Given any starting node. What ...
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### Hamiltonian cycle, verifying and finding

If we have an algorithm that in polynomial time says if a graph G has an hamiltonian cycle, can we have an algorithm that in polynomial time find an hamiltonian cycle? My attempt is to delete an edge ...
222 views

### How to find a path that connects all the dots in the matrix?

I have a matrix that consists of 0, 1, 2. 0 - dot. 1 - block. 2 - start dot (initial position in the path). I have to create a path from the start dot, that connects all the dots in the matrix and ...
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### How complete directed graph with n-vertices is connected to the n-dimensional simplex and its triangulation?

Answer https://stackoverflow.com/a/26151549/1375882 suggests that Sperner's lemma can be used to prove the existence of index for the search Hamiltonian path in complete directed graph. But Sperner's ...
466 views

### Does topological sort exist for any complete directed acyclic graph?

Let's assume that DAG is complete: there is directed edge among every to nodes. Does topological sort of vertices exist for any such graph? I.e. is it possible to make linear list of nodes in which ...
71 views

Given a directed graph $G = (V, E)$, you have been told that a Hamiltonian path $p_0p_1\ldots p_V$ exists with the property that for each edge $p_ip_j$ that is not part of the Hamiltonian path, $i >... 1answer 872 views ### Minimum Path cover in a Directed Acyclic Graph Given a weighted directed acyclic graph$G=(V,D,W)$and a set of arcs$D'$of$D$, where the weights of$W$are on the vertices. The problem is to partition$G$into a minimum number of vertex-... 0answers 45 views ### Non intersecting paths of graphs with obstacle number one There are$N$points inside a polygon. If two points are connected by an edge (a line segment) if the edge is completely inside the polygon. We could conclude finding a Hamiltonian path is NPC, but ... 1answer 73 views ### Hamiltonian non intersecting path in plane$N$points are located in 2D plane. Some of the pair of the points are connected by line segments. What is the complexity of the problem of existence of Hamiltonian non intersecting path? What if we ... 1answer 70 views ### Decomposition of a directed graph into Hamiltonian paths I was wondering if anyone knew of an algorithm that when given a directed graph will split it up into separate Hamiltonian paths. I don't really mind about nodes that can't be added to a path but as ... 1answer 45 views ### Shortest hamiltonian path for different dimension points The shortest Hamiltonian path (solution) for a set of points in$\mathbb{R}^k$(in Euclidean space) changes subject to$k$. For example if for$k=1$, the shortest Hamiltonian path will be the sorted ... 0answers 99 views ### Comparing locally maximal and localy minimal Hamiltonian paths [closed] Let$K_n$be a weighted complete graph on$n$vertices. Two Hamiltonian paths are formed as follows. The first one,$H$, is formed by starting at an arbitrary vertex, and at each stage proceeding from ... 3answers 937 views ### Which of the following problems can be reduced to the Hamiltonian path problem? I'm taking the Algorithms: Design and Analysis II class, one of the questions asks: Assume that P ≠ NP. Consider undirected graphs with nonnegative edge lengths. Which of the following problems ... 1answer 151 views ### Why is Adleman's molecular algorithm for Hamiltonian Path linear? In Adleman's 1994 paper (archived), he describes a method of manipulating DNA molecules in a lab that results in a solution to the Hamiltonian Path problem with high probability. He claims that "The ... 2answers 991 views ### Is the longest Hamiltonian cycle NP-complete? As I understand it to prove something is NP-complete you have to show that it's NP-hard by reducing and a known NP-complete problem to your problem and also prove that it is in NP which you do showing ... 1answer 110 views ### Proving that Hamiltonian Cycle is reducible to a travelling problem? I chanced upon the following question online: A company has two trucks, and must deliver a number of parcels to a number of addresses. They want both drivers to be home at the end of the day. ... 2answers 349 views ### Solve Hamilton Circuit with Hamilton Path I want to show the reduction$HC \leq HP$. Let$G=(V,E)$be my undirected graph. My idea is: For each edge$e=(u,v) \in E$check whether$(V,E\backslash\{e\})$has a Hamiltonian Path. If this is true ... 1answer 60 views ### Can this Arrow-Ring puzzle be encoded as an integer programming problem? I would like to write a solver for these kind of Arrow-Ring puzzles. However, I can't encode all the constraints correctly. I noticed that Sudoku can be solved using integer programming and I am ... 0answers 482 views ### Minimum weight Hamiltonian path on a weighted (0 and 1) tournament graph Suppose we have a weighted tournament graph. (A directed graph in which every pair of distinct vertices is connected by a single directed edge.) The weights are constrained to be 0 and 1. I know ... 1answer 4k views ### Detecting Hamiltonian path in a graph There are various methods to detect hamiltonian path in a graph. Brute force approach. i.e. considering all permutations T(n)=O(n*n!) Backtracking T(n)=O(n!) Using Dynamic programming T(n)=O(2^n * n^... 1answer 614 views ### DAG Hamiltonian Path NP-complete The book computers and Intractability mentions that Hamiltonian Path problem is not NP-complete in DAG. But if Hamiltonian Cycle is NP-complete in digraph then I can split a vertex and create two ... 1answer 1k views ### Hamiltonian path and minimum spanning tree Suppose i have a graph and i want to find minimum-spanning-tree. As in imperative languages we have to take specific steps from everynode(example ,we use kruskal's algorithm or prim's algorithm) to ... 2answers 1k views ### Rearranging strings so that the Hamming distance between them is 1 This is a question from CodeFights.com: Given an array of equal-length strings, check if it is possible to rearrange the strings in such a way that after the rearrangement the strings at ... 1answer 201 views ### Find the$k$-th lexicographically smallest hamiltonian circuit Let's say we have given unweighted directed graph with$N$nodes and$M$edges, and we want to find the$K$-th hamiltonian circuit, ordered in lexicographical order. For example, if we have complete ... 0answers 678 views ### How can the shortest traveling salesman tour be found in$O(2^n poly(n))$time and less than exponential space? I'm stuck on problem 9.4 from The Nature of Computation which reads: Dynamic Salesman. A naive search algorithm for TSP takes$O(n!)$time to check all tours. Use dynamic programming to reduce this ... 1answer 306 views ### Reducing one variant of Hamiltonian path to another Define$A = \{<G,s,t> :G$is un directed graph that has a Hamilton path from$s$to$t\}B = \{<G> :G$is un directed graph that has a Hamilton path$\}$I would like to show that$...
After looking at the definition of nondeterministic TMs, it seems that, while guessing, the machine could go to at most $|Q|\times | \Gamma |$ configurations, being in a particular one. However, if ...