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# Questions tagged [optimization]

For challenges focusing on the optimization of an aspect not covered by other tags. (not a winning criterion)

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### Shortest restricted superstring

Given two sets of strings, $D$ and $R$, find the shortest string which contains every string in $D$, but contains none of the strings in $R$. There are almost always multiple possible ...
• 18.4k
2k views

### Optimally break a string into words

Given a string, like potatocarrot, break it into the smallest number of substrings possible. These substrings can consist either be a single character, or one of a ...
325 views

### Wash clothes as quickly as possible

It's laundry day, and you have lots of clothes that need to be washed. Wanting to have as much time left over for code golf as possible, you hope to optimize how quickly you wash and dry them all. You ...
2k views

### Satisfy as many people as possible

There are times when a large number of people need to choose something. They all want to get the stuff they choose, obviously, but it's impossible to please everyone that way, so a usual compromise is ...
• 2,659
228 views

### Implement constant-latency branchless multiplication efficiently

Modern hardware can perform multiplication very fast in a constant latency of 3~4 cycles. But some tiny chips for embedded environments sometimes lack hardware multiplication, which has to be emulated ...
• 2,121
539 views

### Egyptian fractions summing to n

An "Egyptian fraction" is a list of distinct fractions with a numerator of $1$. For example: $\frac 1 1+ \frac 1 2 + \frac 1 3 + \frac 1 6$ The "size" of an Egyptian ...
• 84.9k
851 views

### High throughput prime numbers

This challenge is inspired by the High throughput Fizz Buzz challenge. The goal Generate a list of prime numbers up to 10,000,000,000,000,000. The output of primes should be in decimal digits followed ...
• 2,121
5k views

### Who Is Kevin Bacon?

You may know the game The Six Degrees of Kevin Bacon, based on the conjecture that every actor in Hollywood can be connected to Kevin Bacon by no more than 6 "co-star" relations, so Kevin ...
• 18.4k
2k views

### Constructing Solar Panels from Squares

I'm designing a new space station for generic super-villain purposes (something something megalaser), but I'm having trouble designing the solar panels. My genius team of scientists can calculate ...
• 11.1k
2k views

### Hunt for discount

Story My local pizza delivery introduced new discount. You get 50% discount from every second item on your order. But being greedy capitalists, they forgot to mention that they will rearrange items ...
• 669
321 views

### Largest Compatible Maze

Background Consider an $n\times n$ grid, where each cell is either empty (denoted by .) or a wall (denoted by #). We say that ...
• 6,216
1k views

### Square root multiples

This code-challenge is based on OEIS sequence A261865. $A261865(n)$ is the least integer $k$ such that some multiple of $\sqrt{k}$ is in the interval $(n,n+1)$. The goal of this challenge is ...
• 8,097
399 views

### Minimal Pairing

Your program should take two lists, where each entry (a positive integer) represents the number of members of some group, as input. These lists will have the same sum but may have different lengths. ...
• 2,997
61 views

### Find two contiguous subarrays with the greatest difference [closed]

Here's an interview question I've seen on a few sites. People claim that an O(n) solution is possible, but I've been racking my brain these last 2 days and I couldn'...
• 121
487 views

### Swaps to Sort an Array

You are given an array $A$, which may contain duplicate elements. In each swap, you may swap the value of any two indices $i, j$ (i.e. switch the values of $A_i$ and $A_j$). What is the least ...
• 659
913 views

### Gerrymander North Carolina

The challenge How well can you gerrymander North Carolina into 13 voting districts? In this challenge, you use the following files to draw different maps for Republicans and Democrats. File 1: ...
• 2,229
918 views

### Find the largest root of a polynomial with a neural network

The challenge Find the smallest feedforward neural network such that, given any 3-dimensional input vector $(a,b,c)$ with integer entries in $[-10,10]$, the network outputs the largest (i.e., "...
• 2,229
1k views

### Sort with a neural network

The previous neural net golfing challenges (this and that) inspired me to pose a new challenge: The challenge Find the smallest feedforward neural network such that, given any 4-dimensional input ...
• 2,229
1k views

### Create a uniquely solvable crossword ... without clues

Can you imagine solving the New York Times crossword puzzle without any clues? Maybe not with all of the creativity and new words and phrases appearing in modern crosswords, but with a fixed word ...
• 2,509
1k views

### Permutations in Disguise

Given a $n$-dimensional vector $v$ with real entries, find a closest permutation $p$ of $(1,2,...,n)$ with respect to the $l_1$-distance. Details If it is more convenient, you can use ...
• 43k
746 views

### Heavy Box Stacking

You have a bunch of heavy boxes and you want to stack them in the fewest number of stacks possible. The issue is that you can't stack more boxes on a box than it can support, so heavier boxes must go ...
• 9,791
464 views

### Multiplication in Brainfuck - minimum number of evaluations [closed]

Given two numbers in tape location #0 and tape location #1 in Brainfuck, compute their product into another tape location (specify with answer). Optimize for the least amount of time-units used, where ...
3k views

### Make me a minimum magic sum

Keeping this challenge short. You are given 4 numbers: p1, p2, p3 and p4. The magic sum of the numbers are defined as follows: ...
• 1,193
1k views

### Can a neural network recognize primes?

Background Recognizing primality seems like a poor fit for (artificial) neural networks. However, the universal approximation theorem states that neural networks can approximate any continuous ...
• 2,509
464 views

### Minimum-cost flow problem

A flow network is a directed graph G = (V, E) with a source vertex s ϵ V and a sink vertex ...
992 views

### Plight of the Concorde

Background The traveling salesman problem (TSP) asks for the shortest circuit that visits a given collection of cities. For the purposes of this question, the cities will be points in the plane and ...
• 2,509
392 views

### Optimizing swiping across a 1D keyboard

This is a code-challenge with a custom scoring system, where the lowest score wins. Introduction Many smartphones allow to enter text by swiping your finger across the 2D virtual keyboard. This ...
• 166k
495 views

### Optimize my wings order

This tweet lists the possible orders for Wings of a Chinese restaurant1: When ordering Pizza I usually calculate what size gives me the best Pizza-price ratio which is a simple calculation. However ...
• 16.3k
248 views

### Optimizing edge selection from a list of numbers

You are given a list, L, with the length N. L contains N random positive integer values. You are only able to select from the outer edges of the list (left/right), and after each selection every value ...
• 61
1k views

### Optimize Compiler for simple Reverse Polish Notation Programming Language

Description Imaginary programming language (IPL) uses Polish Reverse Notation. It has the following commands: i -- input number and push it to the stack o -- non-destructive output top of the stack ...
2k views

### Fruit bagging factory

Your mission is to build an algorithm (program or function) that can optimize packing fruit from a conveyor belt into bags to be sent off to retailers, optimizing for a largest number of bags. Each ...
• 4,917
299 views

### +- knapsack problem

Given a set of items, each with a weight and a value, determine the number of each item to include in a collection so that the total weight is less than or equal to a given limit and the total value ...
• 3,532
531 views

### Egg hunting in Collatz style

Inspired by The Great API Easter Egg Hunt! Summary Your task is to search for a predetermined integer in the "Collatz space" (to be explained later) using the fewest step possible. ...
• 3,566
455 views

### Minimize Least Used Binary Bits in Fractions

Introduction For a given rational number r, find a pair of integers p,q so that p/q=r and ...
• 3,566
665 views

### Sort by shuffling blocks

Block shuffle sort The block shuffle sort is a (rather artificial) method of sorting a list. It works as follows, illustrated by an example. ...
• 42k
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### 1D Hopping Array Maze

Inspired by We do tower hopping and related to 2D Maze Minus 1D Introduction Your task is to find the shortest path to get out of an array maze following specified rules. Challenge A 1D array a with n ...
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### We do tower hopping

Task Given an array of non-negative integers a, determine the minimum number of rightward jumps required to jump "outside" the array, starting at position ...
• 784
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### Integer Linear Programming

Introduction Write a solver for integer linear programming. Challenge Your task is write a solver for integer linear programming (ILP). In ILP, linear inequalities of a set of unknowns (all of which ...
• 3,566
723 views

### Can you outgolf Bill Gates?

Pancake sorting is the colloquial term for the mathematical problem of sorting a disordered stack of pancakes in order of size when a spatula can be inserted at any point in the stack and used to flip ...
43k views

### Write Moby Dick, approximately

Here is a 1.2Mb ASCII text file containing the text of Herman Melville's Moby-Dick; or, The Whale. Your task is to write a program or function (or class, etc. -- see below) which will be given this ...
• 7,102
370 views

### Strategic Vanishers

This post is loosely inspired by this mathoverflow post. A Vanisher is any pattern in Conway's Game of life that completely disappears after one step. For example the following pattern is a size 9 ...
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4k views

### How small can it get?

Starting with a positive integer N, find the smallest integer N' which can be computed by repeatedly dividing N by one of its digits (in base-10). Each selected digit must be a divisor of N greater ...
• 166k
689 views

### Advent Challenge 1: Help Santa unlock his present vault!

Next >> Descriptive Keywords (for searching): Make Two Matrices Equivalent, Overlap, Array, Find Challenge Santa has had a history of elves stealing presents from his vault in the past, so this ...
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303 views

### Bobby's Booby-Trapped Safe

Bobby's booby-trapped safe requires an n-digit code to unlock it. Alex has a probe which can test combinations without typing them onto the safe. The probe responds Fail if no individual digit is the ...
• 2,723
805 views

### Minimum rectangle cover

Rectangle covers Suppose you have a matrix of bits, for example the following. 1 1 0 0 0 1 1 0 1 1 1 1 0 1 1 1 0 1 1 1 0 1 1 1 1 1 0 1 1 1 1 0 1 1 0 1 1 1 0 1 ...
• 42k
276 views

### Fuzzy distances to coordinates

This challenge is similar to my previous one, but has a twist that makes it significantly more difficult. There are n people on a 2D plane. Using distances between them we're going to find their ...
• 38.6k
343 views

### Piles and Piles of Pebbles

My job is stacking pebbles into triangular piles. I've only been doing this for a century and it is already pretty boring. The worst part is that I label every pile. I know how to decompose pebbles ...
• 15.9k
840 views

### Optimal path through a matrix

Given a matrix consisting of positive integers, output the path with the lowest sum when traversing from the upper left element to the bottom right. You may move vertically, horizontally and ...
1 vote
137 views