All Questions
226
questions
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
30
votes
3
answers
27k
views
Perm-Missing-Elem: 100% functional score, but only 60% performance
I cannot figure out why I didn't get 100% success from the Codility's Perm-Missing-Element test even I solve with \$O(n)\$. I will appreciate any advice/answers.
You can see the problem, my code, and ...
- 505
29
votes
5
answers
12k
views
Custom indexOf() without String methods
I created my own indexOf function. I was wondering if anyone could help me come up with a way to make it more efficient. I am practicing for interviews so the catch ...
- 1,499
16
votes
1
answer
205
views
Minesweeper analyze goes to N-Queensland
As @rolfl recently solved the N-Queens problem, I figured that it was time also for me to solve it.
My approach is significantly different from @rolfl's. I quickly realized that the N-Queens problem ...
- 59.2k
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 ...
- 303
13
votes
2
answers
6k
views
Calculate the area of rectangles union
I've been given the following task:
Given N rectangles with edges parallel to axis, calculate the area of the union of all rectangles. The input and output are files specified in program arguments. ...
- 229
11
votes
3
answers
2k
views
Algorithm to calculate semi perfect integers, lack of efficiency
I'm working on an algorithm to calculate weird numbers, and to do so there are several properties that needs to be calculated, one of them being, if it is NOT a semi-perfect/pseudoperfect number.
My ...
- 917
11
votes
2
answers
1k
views
Finding an element in multiple sorted lists efficiently
I have \$k\$ sorted Lists, each of size \$n\$. Currently I have hard-coded 5 sorted Lists each of size 3, but in general that is ...
- 1,947
11
votes
1
answer
2k
views
Backpropagating with Neural Network
I wrote a Java program implementing a neural network with backpropagation. For anyone who isn't familiar with Neural Networks and Backpropagation, here is a good resource. Here is another ...
- 211
10
votes
4
answers
2k
views
Sieve of Eratosthenes optimization
I am making a program to find primes between the given range of numbers. Unfortunately, the algorithm I created is too slow. Do you have any ideas of how to optimize the code?
...
- 245
10
votes
1
answer
2k
views
10
votes
2
answers
1k
views
Unique value finder
For our first assignment in our algorithm class we are suppose to solve several different questions using information from a 2D array. We are also suppose to optimize our code to get more marks on our ...
- 101
9
votes
5
answers
16k
views
Finding the smallest number whose digits sum to N
I tried my hand at a grade XII Board exam program:
Given two positive numbers M and N, such that M is between 100 and 10000 and N is less than 100, find the smallest integer that is greater than M ...
- 193
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 ...
- 341
9
votes
2
answers
3k
views
Finding longest substring containing k distinct characters
Below is my method to find the longest substring having k distinct characters.
I have used Set to keep track of distinct ...
- 477