# Questions tagged [grid]

For challenges involving a grid.

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### The autopilot mode

A helicopter starting at the top left corner is descending (in a 2D space, for the purpose of this question) towards the ground. It has an autopilot mode and a manual mode. The autopilot mode behaves ...
2k views

### Tic-tac-toe with only crosses

Introduction Everyone knows the game tic-tac-toe, but in this challenge, we are going to introduce a little twist. We are only going to use crosses. The first person who places three crosses in a row ...
2k views

### A 4x4 Challenge

There exists a brain game called Enumerate (which I made, based on Takuzu). Your challenge is to play this game. Task Solve a game of 4x4 Enumerate/Takuzu. Receive a starting grid via STDIN or ...
341 views

### Can I live here?

In the game Terraria, one of the game mechanics involves building houses so that an NPC can move in. There is a strict set of rules for what counts as a valid house or not. Here is the list of rules: ...
2k views

### Produce an XOR table

Introduction XOR is a digital logic gate that implements an exclusive or. Most of the times, this is shown as ^. The four possible outcomes in binary: ...
2k views

### Chain reaction of bombs

Introduction: Before the task, here is what every element does on the map: Plain land (X): This does nothing. Destroyed land (...
713 views

### Find my word(s)!

The idea of this challenge is to find all the words from a dictionary on a grid of letters. Your input should come from stdin or function arg and will come in the following format: ...
2k views

### Fill the rows, columns, and diagonals of an NxN grid with 1 through N

Task Given input N, generate and output an NxN grid where each row, column and the two diagonals contain the numbers 1 to N (or 0 to ...
381 views

### Flip the switches

After you wake in a dark room, you see a rectangular grid of lights with corresponding switches. You decide to use a coordinate system with the bottom left light representing (1,1) and the coordinates ...
213 views

### Finding the smallest grid of squares [closed]

Inspiration from Puzzling.SE. Suppose we have an m × n grid such that each element is a base 10 digit. We can read the numbers from such a grid so that we fix a starting element, go to one of the ...
747 views

### The alphanumeric spiral

The task is very simple, when given an input, output one of the following spirals: Input = 1 gives a spiral with the letter A ...
341 views

### Crack the safe!

Inspired by https://puzzling.stackexchange.com/questions/24334/to-catch-a-thief You are given an n by n (...
875 views

### Parse a two-dimensional syntax

Background Alice and Bob are creating a golfing language to win every single PPCG challenge. Alice wants to make a two-dimensional language, like ><>, but Bob prefers a prefix-infix syntax like in ...
621 views

### How varied is my obstacle course?

Background I have constructed a simple obstacle course by placing boxes in a rectangular room. Now I want to count the number of essentially different ways in which it can be solved. I need you to ...
496 views

### Does the fishy road have an end?

I love ><>, ><> is life! 2D langages are amazing! In this challenge, you will have to say if a "fishy" road has an end, while code-golfing. Definition A fishy road is constructed with tiles, ...
543 views

### How should I tile my kitchen?

I recently ordered some new and colorful tiles to replace my boring old white tiling for my kitchen. However, when the tiles arrived, they were all in a weird shape! Therefore, I need a program to ...
2k views

### Number of pieces on a checkers board

Introduction A normal checkers board contains 8 x 8 = 64 squares: You can see that in total, there are 12 white pieces. Black and white always have the same amount of pieces. If there are any more ...
1k views

### Very Simple Grid Marks

Write a program or function that takes in three positive integers, W, H, and N. Print or return a W×H grid of .'s where every Nth ...
378 views

### Loop Detection - not that kind!

The goal of this challenge is to find the direction and area enclosed by a loop. Input: A rectangular grid consisting entirely of these characters: ^v<> (...
2k views

### Gravity simulator

Statement You are given a still of a series of balls falling in a 2D grid. This grid is surrounded by immutable and unbreakable walls so all the action in contained within them. Your task is to ...
275 views

### Fill in the path

Write a program that fills in the paths of a grid of characters (ASCII 20-7E) according to the following rules. The path is governed by eight directional characters: ...
188 views

### Layout my tiles for me

I'm retiling my kitchen with different coloured tiles. In fact, it's going to have at least 2 colours - and 26 colours as a maximum. But, I'm fussy. I want this wall to look random, but sometimes ...
816 views

### Determine winner of Connect 4

You are given a partially filled Connect 4 grid (7x6). O X O X X O X O O X O X O X X O X X X O O X O O O X X O X (Input can be given ...
1k views

### Print a Pentomino Rectangle

Write a program or function that takes no input but prints or returns a constant textual depiction of a rectangle made of the 12 distinct pentominoes: The rectangle may have any dimensions and be in ...
653 views

### Find the largest N digit number in a W by H grid of digits

Write a program or function that takes in a positive integer N and a grid of decimal digits (0 to 9) with width W and height H (which are also positive integers). You can assume that N will be less ...
603 views

### Plumbing Random Paths

Write a program or function that takes in three integers, a width w, a height h, and a step count ...
731 views

### The Traveling O

The world is a five by five array of cells. It wraps on all sides. It can be visualized like... XXXXX XXXXX XXOXX XXXXX XXXXX You are an O. You love to travel the world, and you do so according to ...
417 views

### Where'd that germ go?

Introduction You are a biologist studying the movement patterns of bacteria. Your research team has a bunch of them in a petri dish, and you are recording their activity. Unfortunately, you are ...
169 views

### Coloring the switchboard red [closed]

Question If you are currently on a cell with a value x, you can move to any cell in the same row or column, provided it has a value y such that x > y. This move is called a switch. The input ...
2k views

### Print all 3 by 3 sturdy squares

A sturdy square (akin to a magic square) is an arrangement of the integers 1 to N2 on an N by N grid such that every 2 by 2 subgrid has the same sum. For example, for N = 3 one sturdy square is <...
2k views

### Illustrate the square of a binomial

Given (by any means) two different natural numbers (of any reasonable size), output (by any means) the square of their sum as in the examples below: Given 4 and 3, output: ...
2k views

### Can I Slide Apart The Puzzle?

Write a program or function that takes in a rectangular grid of text where every cell is either an A or a B. All the ...
1k views

### “Fill the Grid” Problem

A challenge with simple rules but non-trivial algorithms. :-) Task Take input in the form of space-separated integers: N A B S Where N is the side length of a ...
3k views

### Invert a Minesweeper Board

Minesweeper is a popular computer game that you have probably wasted time playing where you try to reveal the cells that are mines in a rectangular grid based on hints of how many neighboring mines ...
512 views

### Filling Arbitrary Ice Cube Trays

Suppose this grid of spaces and X's represents the cross section of some strangely shaped empty ice cube trays: ...
534 views

### Cut a pizza into identical slices

This is what I thought this question was going to be, before I fully read it. A group of code golfers walk into The Nineteenth Bite Pizzeria and order a pizza. It comes in an irregular shape, made of ...
2k views

### Dennis, Doorknob, Martin Büttner, Chris Jester-Young - Pizzeria!

Programming Puzzles & Code Golf is about to get a new moderator, Dennis! This challenge is a tribute to him and our other active (or recently active) moderators: Doorknob, Martin Büttner, and ...
3k views

### Shortest universal maze exit string

A maze on an N by N grid of square cells is defined by specifying whether each edge is a wall or not a wall. All outer edges are walls. One cell is defined as the start, and one cell is defined as the ...
6k views

### 40 Numbers in 9 Bytes

There are 40 ways a directed Hamiltonian path can be arranged on a 3×3 grid: This graphic (thanks Sp3000!) shows only the 20 undirected paths. Traverse each colored line in both directions for ...
2k views

### Uniquely separated pixels

For an N by N image, find a set of pixels such that no separation distance is present more than once. That is, if two pixels are separated by a distance d, then they are the only two pixels that are ...
419 views

### Highest perimeter polyomino

This is code golf. The winner is the valid code with the smallest number of bytes. Challenge Given inputs M and N, the width and height of a rectangular grid of squares, output a polygon that ...
715 views

### Grid crossing sequence

If you take a sheet of graph paper and draw a sloped line that goes m units right and n units up, you cross ...
3k views

### Generate boxes!

Your task is to generate boxes using any one ASCII character with respect to the inputs given. Test Cases ...
974 views

### Worst Case Manhattan Exclusion

Imagine a W by H grid of squares that wraps toroidally. Items are placed onto the grid as follows. The first item can be placed on any square, but subsequent items must not be within a Manhattan ...
2k views

### Print all colorings of a 3x3 grid

You have a 3x3 grid. Each cell can be colored black or white. Display all 512 of these colorings. Fewest bytes wins. You can display the grids in any formation as long as they are visually separated ...
784 views

### Count the crossing words

Consider the following standard 15×15 crossword puzzle grid. We can represent this in ASCII art by using # for blocks and ...
7k views

### Rearranging Words

You should write a program which receives two strings as input and outputs a sequence of movements which rearrange the first string into the second. You should use as few moves as you can. Both ...
417 views

### Permutations of the Fifteen Puzzle

The Challenge Consider the following diagram of the Fifteen Puzzle in its solved state: ...