depth-first-search | 易学教程

Create a MST with depth-first search?

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问题 I have a symmetrical graph and created a tree with all shortest path from a random vertex to any other vertex. Can I use the tree to construct a Minimum Spanning Tree(MST)? My algorithm is similar to depth-first algorithm. 回答1: In the worst case, a shortest path tree does not help in finding a minimum spanning tree. Consider a graph where we want to find the MST. Add a source vertex with edges of an identical large length to each other vertex. The shortest path tree from that source consists

How to use DFS on an array

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问题 I have a 1 dimensional list of values, it looks like this "int[] values'". I beleive I have converted it to a 2d list like this : for (int i = 0; i < 4; i++) { for (int j = 0; j < 4; j++) { board[i][j] = values[i * 4 + j]; } } The board is the new 2 dimensional list of values. On the board there are numbers. A 0 means an empty space, a 1 is a green, a 2 is a blue, and a 3 is a red. How would I use depth first search to find a completed path of a certain color? 回答1: Make a 2D array boolean[][]

How to traverse cyclic directed graphs with modified DFS algorithm

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OVERVIEW I'm trying to figure out how to traverse directed cyclic graphs using some sort of DFS iterative algorithm. Here's a little mcve version of what I currently got implemented (it doesn't deal with cycles): class Node(object): def __init__(self, name): self.name = name def start(self): print '{}_start'.format(self) def middle(self): print '{}_middle'.format(self) def end(self): print '{}_end'.format(self) def __str__(self): return "{0}".format(self.name) class NodeRepeat(Node): def __init__(self, name, num_repeats=1): super(NodeRepeat, self).__init__(name) self.num_repeats = num_repeats

Time complexity of depth-first graph algorithm [closed]

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Closed. This question is off-topic. It is not currently accepting answers. Learn more . Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 2 years ago . I am starting to learn time complexity, and I looked in the examples for the time complexity for some simple sort. I wanted to know how do we calculate average time complexity for a depth-first search in a graph with |V|=n and |E|=m ,let the start node be 'u' and end node be 'v'. gabitzish The time complexity for DFS is O(n + m). We get this complexity considering the fact that we are visiting each

How can I store data in a table as a trie? (SQL Server)

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To make things easier, the table contains all the words in the English dictionary. What I would like to do is be able to store the data as a trie. This way I can traverse the different branches of the trie and return the most relevant result. First, how do I store the data in the table as a trie? Second, how do I traverse the tree? If it helps at all, the suggestion in this previous question is where this question was sparked from. Please make sure it's SQL we're talking about. I understood the Mike Dunlavey's C implementation because of pointers but can't see how this part (The trie itself)

Javascript Tree Traversal Algorithm

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问题 I need help traversing a tree structure in a depth first fashion. I can't come up with an algorithm to do it properly. My input is this: [ ["A", "B", "C"], ["1", "2"], ["a", "b", "c", "d"] ] The output should take the form: [ "A/1/a", "A/1/b", "A/1/c", "A/1/d", "A/2/a", "A/2/b", "A/2/c", "A/2/d", "B/1/a", "B/1/b", "B/1/c", "B/1/d", "B/2/a", "B/2/b", "B/2/c", "B/2/d", "C/1/a", "C/1/b", "C/1/c", "C/1/d", "C/2/a", "C/2/b", "C/2/c", "C/2/d" ] 回答1: This should do the job: function traverse(arr) {

How to properly label branches of a tree in a depth first search

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问题 I have a tree with a structure like this: __2__3__4 / \__5__6 0__1___7/__8__9 \\ \\__10__11__12 \__ __ __ 13 14 15 Node 1 has four children (2,7,10,13), nodes 2 and 7 have two children each (both sharing node 5 as a child). What I am trying to do is create a CTE that provide records containing the parent node, the node, the distance away from the root, and the branch (or fork) its contained in. IF (OBJECT_ID('tempdb..#Discovered') IS NOT NULL) BEGIN DROP TABLE #Discovered END CREATE TABLE

How to implement a breadth first search to a certain depth?

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问题 I understand and can easily implement BFS. My question is, how can we make this BFS limited to a certain depth? Suppose, I just need to go 10 level deep. 回答1: You can do this with constant space overhead. BFS has the property that unvisited nodes in the queue all have depths that never decrease, and increase by at most 1. So as you read nodes from the BFS queue, you can keep track of the current depth in a single depth variable, which is initially 0. All you need to do is record which node in

Simple Java 2d array maze sample

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I am working or understanding how to create a simple java 2d maze that should look like this: int [][] maze = { {1,1,1,1,1,1,1,1,1,1,1,1,1}, {1,0,1,0,1,0,1,0,0,0,0,0,1}, {1,0,1,0,0,0,1,0,1,1,1,0,1}, {1,0,0,0,1,1,1,0,0,0,0,0,1}, {1,0,1,0,0,0,0,0,1,1,1,0,1}, {1,0,1,0,1,1,1,0,1,0,0,0,1}, {1,0,1,0,1,0,0,0,1,1,1,0,1}, {1,0,1,0,1,1,1,0,1,0,1,0,1}, {1,0,0,0,0,0,0,0,0,0,1,0,1}, {1,1,1,1,1,1,1,1,1,1,1,1,1} }; Ones this has been created the idea is to set a starting point and goal point and by using recursive depth first find the path. but must say i am having difficulties to create the maze. Do you

Non-recursive Depth-First Search (DFS) Using a Stack

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问题 Ok this is my first post on Stack Overflow I have been reading for a little while and really admire the site. I am hoping this is something that will be acceptable to ask. So I have been reading through Intro to Algorithms (Cormen. MIT Press) all the way through and I am up to the graph algorithms. I have been studying the formal algorithms laid out for breadth and depth first search in very fine detail. Here is the psuedo-code given for depth-first search: DFS(G) ----------------------------