Questions tagged [breadth-first-search]
In graph theory, breadth-first search (BFS) is a graph search algorithm that begins at the root node and explores all the neighboring nodes. Then for each of those nearest nodes, it explores their unexplored neighbor nodes, and so on, until it finds the goal.
177 questions
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Leetcode: Number of Islands - BFS (Queue vs Recursion)
I was playing around with leetcode's Number of Islands.
As per the challenge's description:
Given an m x n 2D binary grid grid which represents a map of '1's
(land) and '0's (water), return the ...
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Breadth-first search [closed]
there are some problems in this code that I can't think of a solution. It does work for print(real_path,count) but the real thing I want is return real_path,count and for doing this I need to make the ...
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Order of values in dfs and bfs
Let's consider a matrix of integers m:
[[1,2,3]
[4,5,6]
[7,8,9]]
Which represents a graph:
...
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Breadth-first search implementation for finding edge of grid c++
I have implemented a breadth-first search algorithm to find the distance from a point to an edge of a grid. The grid consists of spaces that may have walls between them, effectively blocking certain ...
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Find center of an undirected graph
Task: implement an algorithm to find graph center \$Z(G)\$ given undirected tree \$G\$.
This is my first time programming in C++ so any (elementary) feedback is appreciated.
The way I did it is:
Run ...
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LeetCode 126: Word Ladder II -- Memory limit exceeded
I am trying to solve LC126, and got a memory limit exceeded for the following solution.
I've seen the answer here -- so I'll try to use Dijkstra as well, but I would like to understand why I get the ...
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Optimizing BFS code to find connected components in a graph
I am writing a Python code to find the connected components of a graph using BFS. The code works but takes a long time to run. Please suggest possible optimizations of my code.
The graph is stored as ...
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performance - Word ladder leetcode
I am working on Word Ladder - LeetCode
Given two words (beginWord and endWord), and a dictionary's word list, find the length of shortest transformation sequence from beginWord to endWord, such that:
...
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Find the shortest path from bottom left to top right in a maze using dfs and bfs algorithm
The following code is applying the depth-first search and breadth-first search algorithm to find the shortest path from bottom left to top right in a 10 x 10 grid. ...
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How to create a maze solve search with BFS provide navigation movements
How should I structure this code to create a maze, solve it with breath-first-search (BFS) and to provide basic navigation movements by 1 step within maze with number of moves required to navigate? ...
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Breadth first search on trees in Haskell
I'm writing a breadth first search algorithm in Haskell that supports pruning. It is guaranteed that the search will never encounter nodes that have been visited before, so I implemented the search as ...
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PureScript breadth-first search implementation
For context, I wrote a function, get_servers, for the game Bitburner which is usually played by writing JavaScript code. Instead, I used PureScript to write the ...
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2D Map Optimization via Beam Search in Python
This is a problem based on the game "NGU Industries" in which the objective is to build a factory. Each tile can hold either a production building or a "beacon" which increases the ...
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Find the first repeating sequence in digits of pi
I wrote a function to return the first n length sequence which occurs twice in the digits of pi. Along with the repeated sequence, I want the indices of the first and second occurrences. For example, ...
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Breadth First Search Block Puzzle
I am creating a program that will be given a text file as input with the board's dimension and the piece ID along with the piece width and length. The goal is to arrange all blocks in the board ...
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Python PacMan with son
I have been coding 'Pac-Man' with my 16yo. A hopefully not too boring project to help improve his Python coding. We have just moved the 'Ghosts' into a class which was a good first introduction to ...
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01 Matrix is too slow when solved using DFS
I tried solving Leetcode 01 Matrix problem.
It is running too slow when solved using DFS approach.
Given a matrix consists of 0 and 1, find the distance of the nearest 0 for each cell.
The distance ...
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K-clustering algorithm using Kruskal MST with Disjoint Set in place to check for cycles
here below a working implementation that finds the minimal distance between k(set =4 below) clusters in a graph.
I have doubts mainly on the implementation of the ...
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Generating unique 2D numpy arrays with 2 adjacent row elements swapped while using BFS in Python
So I have a 12 x 6 2D numpy array for input which consists of 7 possible board objects (characters from 'abcdefg'). From a 2D numpy array I wish to generate all the possible unique 2D arrays, in whose ...
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Breadth First Search Python Implementation
I have the below implementation of the BFS algorithm, in which I've used OrderedDict instead of a list or ...
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Depth First Search vs Breadth First Search
So after years of teaching myself, I think I'm ready to stand on the shoulders of giants and ask you a good question!
I have a tree of nodes. What I want is a function that returns an array of the ...
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Parsing a Graph To Convert It Into Adjacency Lists And CSR And Then Make Connection Queries Using Bidirectional BFS
I was assigned an university project where I had to parse directed graph files coming from SNAP and then convert them into CSR (Compressed Sparse Row) format. Then the client must have the ability to ...
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Is this breadth-first search correct?
I wrote a program that is supposed to be a breadth-first search algorithm, but I'm very new to search algorithm so I don't know if my method is very effective or if there is a simpler way to do this. ...
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Finding shortest path in matrix
Given an N x N matrix of positive integers, I need to find the shortest path from the first cell of matrix to the last cell of matrix. I can move exactly x steps from any cell, where x is the value of ...
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Breadth-first search(BFS) Implementation in Python 3 [closed]
I have implemented a BFS. Does this look like a proper implementation of BFS in Python 3? And if you think something needs to be improved, say it.
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LeetCode: Rotting Oranges in C#
https://leetcode.com/problems/rotting-oranges/
Please review for coding style in 40 minutes job interview.
In a given grid, each cell can have one of three values:
the value 0 representing an ...
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Maze image solver and animator in Python
This maze solver is a continuation to the maze generator I posted here recently Maze generator & animator in Python
This code takes an image containing a 2-color maze as input and solves the maze ...
user203258
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Determine if a string is a sequence of dictionary words
This is Leetcode problem 139: "Wordbreak"
Problem: Given a non-empty string s and a dictionary wordDict
containing a list ...
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Javascript Tree Class 2
This question is the second version of the code here.
I'm writing a general tree class. Specifically, each node should have oen parent, some number of children, and hold a value.
I'm looking for ...
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Javascript Tree Class
I got caught in the trap of implementing my own data structure. I've created a very general tree structure, where each node gets one parent, some children, and holds a value.
I'm mostly looking for ...
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Optimising the BFS
The input graph to the bfs function is in the form of edge list representation.
...
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(Leetcode) Snakes and Ladders
This is a Leetcode problem -
On an \$N\$ x \$N\$ board, the numbers from 1 to N * N are
...
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(Leetcode) Escape a large maze
This is a Leetcode problem -
In a 1 million by 1 million grid, the coordinates of each grid square
are (x, y) with \$0\$ \$<=\$ ...
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(Leetcode) K-similar strings in Python
This is a Leetcode problem -
Strings A and B are K-similar (for some non-negative integer
...
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(Leetcode) Sliding puzzle in Python
This is a Leetcode problem:
On a 2 x 3 board, there are 5 tiles represented by the integers 1
through ...
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Leetcode: Find-bottom-left-tree-value
https://leetcode.com/problems/find-bottom-left-tree-value/
Given a binary tree, find the leftmost value in the last row of the tree.
Example 1:
Input:
...
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LeetCode: Employee-importance BFS
You are given a data structure of employee information, which includes
the employee's unique id, his importance value and his direct
subordinates' id.
For example, employee 1 is the leader of ...
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Rubik's Cube in Java
I have this Java implementation of a Rubik's cube's state. My primary concern is DRYness of my code:
RubiksCubeNode.java
...
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Breadth-first search in Java: Competitive style - follow-up
I have improved my BFS in Java according to vnp's suggestions. Again, we wish to find shortest paths in directed unweighted graphs using BFS, competitive style (no ...
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LeetCode: N-ary Tree Level Order Traversal
https://leetcode.com/problems/n-ary-tree-level-order-traversal/
Given an n-ary tree, return the level order traversal of its nodes' values. (ie, from left to right, level by level).
For example, ...
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LeetCode: maximum-depth-of-n-ary-tree
https://leetcode.com/problems/maximum-depth-of-n-ary-tree/
Given a n-ary tree, find its maximum depth.
The maximum depth is the number of nodes along the longest path from the root node down to the ...
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Breadth-first search in Java: competitive style
Here my attempt was to write a graph algorithm the way a competitive programmer would write under time pressure. The problem to solve was to find a shortest path in a directed, unweighted graph using ...
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Object-Oriented Breadth-First Search Implementation
My goal is to write a GUI application where a user can create a maze and select an algorithm. The passage of the algorithm from a selected start and end point should be visualized.
The following ...
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Find the shortest path between two points in a 2D matrix with obstacles
I need to find shortest path between two points in a grid given an obstacles..
Given a 2 dimensional matrix where some of the elements are filled
with 1 and rest of the elements are filled. Here X ...
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Find the longest connect cells region per color
I have been studying graphs/BFS/DFS. working on wrapping my head around the following problem
Given a grid [m,n] where each cell has a value denotes a color, find the longest connected region that ...
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Java breadth-first search for finding the shortest path on a 2D grid with obstacles
Please review my Breadth-first search algorithm implementation in Java for finding the shortest path on a 2D grid map with obstacles.
The findPath() method ...
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Maze solver BFS in Haskell
I am really excited that I just wrote my Haskell maze solution in bfs. This is my very first haskell (and I still haven't tried to build a maze in haskell so that maze is hard coded xD)
ANY ...
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Pramp: Sales path
the question is taken from Pramp(really cool site!)
there is a more straight forward solution.
using recursion. but I thought trying it using BFS.
please review only the code of GetCheapestCost ...
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BFS Pathfinding algorithm using Javascript generator
I'm implementing a BFS traversal in a grid-like structure. Because I wanted to experiment with ES6 Generators for a long time, I thought I'd implement the search using that abstraction.
I am sure ...
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Flood Fill using unordered_map which has user-defined type as key
I have an implementation of the flood fill algorithm. Assume that an image is provided as a vector of ...
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