# Tag Info

Accepted

### BFS Implementation in Python 3

sets perform containing checks (w in visited) $O(1)$ rather than $O(n)$ for lists. ...

### 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

### BFS Implementation in Python 3

I agree with Mathias Ettinger's use of sets and deques, with two changes: name the set seen ...
• 191

### 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: ...
• 17k
Accepted

### Solve 8-tile sliding puzzle

Here's the code you want to speed up: ...
• 19.3k
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 ...
• 5,522

### 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 ...
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 ...
• 7,421
Accepted

Will be fixed soon Advice 1 In BFS, you don't really need colors. (See alternative implementation.) Advice 2 (Exposing internals) ...
• 27k
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
Accepted

### Shortest path on a maze with keys and doors

Treatment of Keys You're doing a whole lot of extra work - both in terms of actual operations and code - the way you're treating keys. You're copying the entire maze everytime you get a key, and ...
• 18.4k
Accepted

### Breadth first search implementation (also includes functions for finding shortest path and number of connected components)

First, Queue is an unnecessary abstraction. JS arrays already provide methods to make it act like a queue. Use them directly instead. Next is that your logic is ...
• 25k

### C++ Graph Implementation

Pointer to vector? You have two members: a pointer to a vector (which you new, but never delete, which leads to several other ...
• 18.4k
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 ...
• 11.6k
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 ...
• 1,198

### 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 @...
• 2,884
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 ...
• 17.2k

### C++ Graph Implementation

First of all, why do you use a raw pointer for std::vector<int>* Adj; you can simply use ...
• 5,102
Accepted

### Recursive Breadth First Search for Knights Tour

I see a number of things that could help you improve your code. typedef struct is not needed in C++ In KMBaseData.h, the code ...
• 65.3k

### Graph theory using C++ STL

I see some things that may help you improve your program, but first let me thank you for asking a good question with a complete sample program. It makes things much easier to review and provides ...
• 65.3k

### 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 ...
• 28.5k
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 ...
• 4,201
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 ...
• 2,653
Accepted

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 \...
• 27k
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 ...
• 9,100

### 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 ...
• 44.2k
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
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 ...
• 50.5k