All Questions
226
questions
3
votes
1
answer
219
views
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 ...
- 21.6k
5
votes
1
answer
337
views
Leetcode: Largest Number
I was trying out leetcode's Largest Number.
As per the challenge's description:
Given a list of non-negative integers nums, arrange them such that
they form the largest number and return it. Since ...
- 62.8k
4
votes
2
answers
496
views
Leetcode: Steps to Make Array Non-decreasing
I was trying out leetcode's Steps to Make Array Non-decreasing
As per the challenge's description:
You are given a 0-indexed integer array nums. In one step, remove all
elements nums[i] where nums[i ...
- 341
9
votes
4
answers
2k
views
Leetcode : First Missing Positive
I was trying out leetcode's first missing positive.
As per the challenge's description:
Given an unsorted integer array nums, return the smallest missing
positive integer.
You must implement an ...
- 41
5
votes
2
answers
8k
views
Simplified regular expression engine
Task:
On an alphabet set [a-z], a simplified regular expression is much
simpler than the normal regular expression.
It has only two meta characters: '.' and '*'.
'.' -- exact one arbitrary character ...
- 43.4k
2
votes
1
answer
737
views
Traverse a list of tree nodes
I am wondering if there is a better way to traverse a list of trees.
Here is my current algorithm:
Collect the parent IDs in a Map
Traverse all the groups and find ones where their ID is not in the ...
CommunityBot
- 1
2
votes
2
answers
338
views
Finding all the prime factors of a number
I want to calculate all the prime factors of a number in the range 2 ≤ N ≤ 107. Here is my function:
...
- 77.3k
1
vote
0
answers
74
views
A parallel MSD radix sort in Java for integer keys
I have this repository: https://github.com/coderodde/ParallelRadixSort.java/tree/main
It contains a parallel MSD radix sort presented below:
...
- 28.9k
4
votes
2
answers
663
views
Merge a list of deeply nested HashMaps
Suppose I have a list of hashmaps (<String, Object>). Values can be either scalar types or a nested HashMap with the same type.
I need to merge a list of this ...
- 6,519
4
votes
1
answer
2k
views
ByteLandian challenge from CodeChef
I am trying to go through the problems on CodeChef and came across this problem:
In Byteland they have a very strange monetary system. Each Bytelandian
gold coin has an integer number written on ...
- 6,519
1
vote
0
answers
129
views
Making Robert Tarjan's offline LCA algorithm run (much) faster (Java)
I have produced this GitHub repository that compares the performance of:
Robert Tarjan's off-line lowest common ancestors algorithm,
An improvement of the above algorithm.
Typical demo program ...
- 28.9k
62
votes
3
answers
4k
views
Analyzing Minesweeper Probabilities
Calculating probabilities in Minesweeper might sound like an easy task, but I've seen so many probability calculators that's either incorrect, horribly slow, or with ugly code (or all of them) so I ...
- 59.2k
0
votes
3
answers
1k
views
Calculate square of (sum of even-indexed) - (sum of odd-indexed) subarrays from an array
Find all subarrays from a given array in the least possible time complexity.
Requirement:
calculate the square of (sum of even-indexed elements) - (the sum of odd-indexed elements) of al the subarrays....
- 21
13
votes
8
answers
9k
views
Sieve of Eratosthenes
For practice, I've implemented Sieve of Eratosthenes in Java by thinking about this visual animation.
I would like to hear some suggestions for improvements, especially how to make it more efficient ...
- 151
5
votes
4
answers
553
views
Fastest function to find cumulative largest perfect squares of a single number?
I'm attempting to write an algorithm that will find the largest perfect squares of a given integer, subtracting their values from the total each time, as fast as possible. It's somewhat hard to ...
- 4,822