All Questions
19 questions
59
votes
9
answers
14k
views
Project Euler problem 1 in Python - Multiples of 3 and 5
I'd like suggestions for optimizing this brute force solution to problem 1. The algorithm currently checks every integer between 3 and 1000. I'd like to cut as many unnecessary calls to ...
- 699
2
votes
1
answer
2k
views
Fast Prime Sieve (Python Implementation)
A modified version of the prime sieve. I actually doubt it could be implemented any faster, but I might be wrong:
...
- 1,792
3
votes
1
answer
219
views
Stable reversed Tartaglia's triangles
Inspired by Minimising the triangle
I am writing a fully tested program to solve the following problem:
A triangle needs a good foundation. Every row in the triangle is derived from the sum of the ...
- 27.9k
2
votes
1
answer
2k
views
Extract data from large JSON and find frequency of contiguous sub lists
I have been writing some code (see component parts here and here) that:
Takes a very large JSON (15GB gzipped, ~10million records)
Extracts the relevant parts of the JSON into a list of lists
Creates ...
- 85
2
votes
3
answers
404
views
Most effective search algorithm for guessing list of strings via function returning bool if substring is in list using Python
I trying to figure out the most effective way to accomplish this task:
A function, check(), contains a list of strings. Calling the function with a string as ...
- 21
5
votes
1
answer
242
views
Calculating the energy of the harmonic oscillator using a Monte Carlo method
The problem
The partition function for the quantum harmonic oscillator can be written in the path integral formulation as
$$Z\propto\int Dx(\tau)\exp\left(-\frac{S_E}{\hbar}\right)=\int Dx(\tau)\exp\...
15
votes
1
answer
13k
views
Rotating greyscale images
For educational purposes I wrote a little piece of code to rotate greyscale images as "low level" as possible, that is, not using any rotate() function, but doing ...
- 464
10
votes
2
answers
513
views
Naive implementation of KMP algorithm
After reading this answer to the question "High execution time to count overlapping substrings", I decided to implement the suggested Knuth-Morris-Pratt (KMP) algorithm. I used the pseudo-code listed ...
- 41.3k
9
votes
1
answer
9k
views
Find the nearest point of a given set of points
Suppose there are a set of given points (represented by x and y two dimensional coordinates), and for any given point A, I want ...
- 3,493
9
votes
2
answers
2k
views
Hash table solution to twoSum
I try the most to solve a twoSum problem in leetcode
Given an array of integers, return indices of the two numbers such that they add up to a specific target.
You may assume that each input ...
- 595
8
votes
1
answer
3k
views
Project Euler 407: Is there any more optimal way to solve this idempotent equation (modulo n ring)?
Project Euler problem 407:
If we calculate a2 mod 6 for 0 ≤ a ≤ 5 we get: 0, 1, 4, 3, 4, 1.
The largest value of a such that a2 mod 6 = a is 4.
Let's call M(n) the largest value of a < n ...
7
votes
2
answers
6k
views
Sherlock and The Beast
I have recently written the program for the Sherlock and The Beast' HackerRank challenge. That's working fine, but the problem is that it takes too much time if a big number is given as a input. I ...
6
votes
3
answers
821
views
Python script to split overlapping ranges, version 4
This is the fourth iteration of a Python script I wrote that splits overlapping ranges, and this is the fastest version I have wrote so far, and also a version that works for all inputs. I have done ...
- 3,426
5
votes
1
answer
5k
views
Find if one list is a subsequence of another
So the problem of verifying if a list is a subsequence of another came up in a discussion, and I wrote code that seems to work (I haven't rigorously tested it).
IsSubequence.py
...
- 1,792
5
votes
1
answer
7k
views
Finding missing items in an int list
Here is a problem I am trying to solve: trying to find missing photographs from a sequence of filenames. The problem boils down to: given an unsorted list of integers, return a sorted list of missing ...
- 730