All Questions
12 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
3
votes
4
answers
3k
views
Sieve of Eratosthenes: making it quicker
I was thinking about doing problem 23 of Project Euler. It includes the difficulty where you have to factorize primes. I had already done that in problems I solved earlier, but it was only necessary ...
Ief2
6
votes
2
answers
814
views
4 sum challenge (part 2)
This is a continued discussion from (4 sum challenge) by return count only.
Problem
Given four lists A, B, C, D of integer values, compute how many tuples
(i, j, k, l) there are such that A[i]...
- 3,493
14
votes
1
answer
329
views
Recover flights from found tickets
I just found a whole bunch of plane tickets that only have a start and destination on them. I also know the route started in a certain city. I would like to recover the (alphabetically) first possible ...
- 459
13
votes
5
answers
2k
views
Array manipulation: add a value to each of the array elements between two given indices
This is a Hackerrank problem: https://www.hackerrank.com/challenges/crush/problem
You are given a list of size \$N\$, initialized with zeroes. You have
to perform \$M\$ operations on the list and ...
- 1,159
10
votes
4
answers
3k
views
First non-repeating Character, with a single loop in Python
I recently tried to solve the first non-repeating character problem. Please tell me if my solution is valid. I'm aiming for O(n) with a single loop.
My thinking is, it would be easy to tell you what ...
- 203
10
votes
5
answers
869
views
Minimum perfect squares needed to sum up to a target
I'm trying to solve this problem
Given a positive integer n, find the least number of perfect square
numbers (for example, 1, 4, 9, 16, ...) which sum to n.
I've come up with a solution that works ...
- 1,051
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 ...
5
votes
0
answers
434
views
4 sum challenge [duplicate]
Problem
Given four lists A, B, C, D of integer values, compute how many tuples
(i, j, k, l) there are such that A[i] + B[j] + C[k] + D[l] is zero.
To make problem a bit easier, all A, B, C,...
- 3,493
5
votes
3
answers
14k
views
Diagonal difference
Given
You are given a square matrix of size \$N×N\$. Calculate the absolute difference of the sums across the two main diagonals.
Input Format
The first line contains a single integer N. The next ...
- 5,137
4
votes
3
answers
10k
views
Project Euler #3 Largest prime factor
Given
The prime factors of 13195 are 5, 7, 13 and 29.
What is the largest prime factor of the number 600851475143 ?
Solution
...
- 5,137