All Questions
151 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
17
votes
2
answers
2k
views
Yandex programming contest: Alarms
I've tried to solve this challenge about 4 hours during the contest, but all my attempts exceeded the time limit. I tried to solve it with min-heap, but can't pass all the tests. How it can be solved ...
- 281
14
votes
5
answers
3k
views
Advent of Code 2019: Day 4
Advent of Code 2019: Day 4
I'm doing Advent of Code this year. Below is my attempt at day 4:
Problem
Part One
--- Day 4: Secure Container ---
You arrive at the Venus fuel depot only to discover it's ...
- 1,792
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
14
votes
1
answer
3k
views
3-Sum Problem in Python
I attempted the 3-Sum problem on Leetcode, where the problem asks to find all possible triplets of numbers in a given list such that their sum is 0. My code worked, but it exceeded the time limit for ...
- 243
14
votes
3
answers
7k
views
Maze solver and generator in Python
After watching Computerphile's video I decided to create my own maze solver and generator in Python. I've never written anything in Python so I'd like to get some feedback about my code, specifically ...
- 143
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
11
votes
3
answers
6k
views
Algorithm for competing cells of 0s and 1s
I'm working on a practice algorithm problem, stated as follows:
There are eight houses represented as cells. Each day, the houses compete with adjacent ones. 1 represents an "active" house and 0 ...
- 213
11
votes
3
answers
2k
views
Pigeon and grain problem: find time until all the grain is eaten
Problem:
There are \$n\$ pigeons and \$m\$ grains. Pigeon \$i\$ eats a single grain every \$x_i\$ seconds. Find the time until all the grain is eaten.
Input:
A line with the integer \$...
- 213
11
votes
1
answer
2k
views
"Mixing Proteins" HackerRank challenge
I am doing this problem on HackerRank and I'm failing test cases because it's taking too long to run when n and k get over 8000. I believe the dictionary lookup should be \$O(1)\$ while lists are \$O(...
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
10
votes
2
answers
4k
views
Generate all valid combinations of n pair of parentheses
Implement an algorithm to print all valid (e.g. properly opened and
closed) combinations of n pair of parentheses.
Following is my implementation and I think it works. Is the algorithm efficient? Do ...
- 539
10
votes
1
answer
1k
views
Programming Challenge from Kattis: Apparatus
I am trying to solve apparatus problem, paraphrased below.
There is an apparatus with n on/off switches with a one-to-one correspondence to n lights (but with an unknown permutation).
We have ...
- 241
10
votes
2
answers
956
views
Finding all contiguous sublists such that each member appears an even number of times
The program needs to find all contiguous sublists of numbers where the number of occurrences of every member in the contiguous sublist is divisible by 2.
The first line of input is N (the number of ...
- 215