# 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: ...
• 32.7k
Accepted

### Solve 8-tile sliding puzzle

Here's the code you want to speed up: ...
• 19.4k
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

### 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 ...
• 7,431
Accepted

Will be fixed soon Advice 1 In BFS, you don't really need colors. (See alternative implementation.) Advice 2 (Exposing internals) ...
• 29.1k
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

### 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
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

### 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
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
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

### 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
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
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 \...
• 29.1k
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

### 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
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
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 ...
• 60.1k

### 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
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
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
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
Accepted