37
votes
Accepted
BFS Implementation in Python 3
sets perform containing checks (w in visited) \$O(1)\$ rather than \$O(n)\$ for lists.
...
- 28.9k
14
votes
Read CSV and use bidirectional BFS to find the shortest connections between actors
It looks like you found a pretty nice approach there already.
A few general things stand out:
Using globals
Magical constants and unsafe C-style arrays/raw pointers:
...
- 1,322
9
votes
BFS Implementation in Python 3
I agree with Mathias Ettinger's use of sets and deques, with two changes:
name the set seen ...
- 191
9
votes
Binary Search Tree BFS iteratively
Much of the code looks good. Some comments could be clearer, and there are some correctness issues.
In is_leaf(), please strike this redundant remark:
...
- 32.7k
9
votes
Accepted
9
votes
Accepted
Find the first repeating sequence in digits of pi
How do I make it simpler and faster?
A more efficient approach:
Iterate on pi with a sliding window of size n.
Save each ...
- 5,614
8
votes
Number of Islands in a 2d grid
One way to simplify the problem is a shift of datastructure to hold your islands. By converting the grid to a set containing only the "land" parts, you can speed up ...
- 28.9k
8
votes
Accepted
Iterator for BFS binary tree traversal
I'll ignore the 'PluralSight' code.
Note that you have implemented a breadth-first traversal. As far as I'm concerned, a spec which doesn't specify how the tree is traversed is insufficient, but you ...
- 7,431
7
votes
Accepted
Breadth First Search using adjacency list
Will be fixed soon
Advice 1
In BFS, you don't really need colors. (See alternative implementation.)
Advice 2 (Exposing internals)
...
- 29.1k
7
votes
Accepted
Perform BFS on a Binary Tree
PEP-0008: your method names should follow snake_case style, and there should be a space between arguments. So change your method singature to:
...
- 434
6
votes
Accepted
Cows with walkie-talkies (USACO Silver Prob. #3; December '16 )
I'd say that this code has the right amount of verbosity - not too terse, not too wordy. It's very readable, with one exception I'll mention below. In order to assess the performance, I'd probably ...
- 11.7k
6
votes
Accepted
Number of Islands in a 2d grid
Complexity
Each cell will be accessed at most 5 times (once to check itself, once per each neighbour that are on land, as part of their BFS search).
This means your overall complexity is O(n) (n ...
- 1,228
6
votes
Number of Islands in a 2d grid
It seems that someone has copied @MathiasEttinger's answer claiming it as their own and posted another question on CR asking for feedback on "their" solution. So here are my improvements to @...
- 2,894
6
votes
Accepted
Degrees of Wikipedia
I think you can potentially remove the impact of the network altogether by using offline Wikipedia dumps. Wikipedia itself asks to not crawl them:
Suppose you are building a piece of software that ...
- 17.3k
5
votes
Accepted
Find the shortest path through a maze with a twist: you can knock down one wall
So here is my version of your code. Changes made:
1. pep8:
I changed the code to more closely conform to pep8. This is important when sharing code as the consistent style makes it much easier for ...
- 4,216
5
votes
Cows with walkie-talkies (USACO Silver Prob. #3; December '16 )
A word on programming competitions
I realize that when solving a problem from a programming competition, you aren't going to end up with the nicest code. It's more about getting something that works ...
- 28.6k
5
votes
Accepted
Binary Search Tree BFS iteratively
[Caveat: This review is premised on a rigorous technical interview context. It takes the specification literally.]
High order bit
To me, the code does not really meet the specification.
The ...
- 2,663
5
votes
Accepted
C++ breadth-first search using adjacency matrix
A bug
The path printed by main (1, 3, 4, 6, 7) is not shortest. The culprit is the printPath: it needs to know, for each node \...
- 29.1k
5
votes
Accepted
Breadth First Search implementation in Python 3 to find path between two given nodes
Comments
Provide a docstring, detailing what the code does and returns
Pep-8
When writing Python, it is advised to follow the styleguide. This means snake_case ...
- 9,130
5
votes
Iterator for BFS binary tree traversal
Bug
There's a bug in your Reset method.
public void Reset()
{
_current = null;
}
It should also be resetting the ...
- 44.3k
5
votes
Accepted
Flood Fill using unordered_map which has user-defined type as key
I'll ignore questions 1 and 5 regarding hashing, because you don't need a hash function at all.
Storing image data
A std::vector<std::vector<int>> is, ...
- 6,217
5
votes
Accepted
Breadth-first search(BFS) Implementation in Python 3
There are a few PEP8 issues:
In Python3, class definitions have been overhauled a bit, and one can simply do class Node: instead of ...
- 456
5
votes
Accepted
Find center of an undirected graph
Don't use <bits/stdc++.h>
The header file <bits/stdc++.h> is not part of the C++ standard, and there is no guarantee ...
- 60.1k
4
votes
Create a complete binary tree and do level order traversal on it
using namespace std;
using namespace std;
Why is “using namespace std;” considered bad practice?
The particular problem I ...
- 21.7k
4
votes
Accepted
Minimum number of flight segments using breadth-first search
1. Review
There's no docstring. What does this function do? What arguments does it take? What does it return?
The code uses a list to represent the queue of nodes to be visited. But if you look at ...
- 49.7k
4
votes
Accepted
Storing configurations of states to a database - Breadth First Search
Prefer interfaces to implementations
public static ArrayList<State> findNeighbours(State currentState) {
Consider
...
- 21.7k
4
votes
Accepted
Hackerrank: KnightL on a Chessboard
Main routine can be simplified
There are a few things about your CalculateStepsFromLeftTopToBottomRight() function that I feel could be simplified:
No need to use <...
- 28.6k
4
votes
Accepted
Word Ladder JavaScript Implementation
Naming
I suggest renaming getShortestPathBetweenWords() to findShortestLadderDistance() for the following reasons:
get is ...
- 1,925
4
votes
Accepted
Performance of BFS in Python 3
1. Review
The bfs function relies on a global variable distance. This make it hard to test (you have to remember to set up the <...
- 49.7k
Only top scored, non community-wiki answers of a minimum length are eligible