The puzzles tag is for discussing algorithms and design approaches for solving programming puzzles. Puzzle competitions or contests should be asked at Programming Puzzles & Code Golf.

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167
votes
1answer
95k views

Where can I find programming puzzles and challenges? [closed]

I'm trying to find places where I can hone my craft outside the context of school or work. Are there places online, or books available, where I can access lists of programming puzzles or challenges?
2
votes
2answers
126 views

Algorithm to solve this “treefarm” puzzle

How would I go about writing a program to solve this kind of puzzle: The green squares represent trees, and you have to plant them in such a way, so that: Trees do not touch each other at all (not ...
3
votes
3answers
114 views

Find a line that is closest to scattered points

I came across the below interview question on Glassdoor: A scatter graph of points on a page, draw a horizontal line across the page such the the perpendicular y distance to the line from all ...
5
votes
1answer
522 views

Compute Adjacent Pair

I was given the following problem: Integer V lies strictly between integers U and W if U < V < W or if U > V > W. A non-empty zero-indexed array A consisting of N integers is given. A ...
2
votes
1answer
259 views

Solving a Sudoku variant with an unknown element

I recently stumbled upon a special Sudoku variant and am now struggling to effectively solve it programatically. Consider the following initial 6x6 grid: The rules The red question mark is ...
8
votes
4answers
568 views

Are Quines useful as anything more than a programming puzzle?

Quines, which are programs that generate their own code as part or all of their output are a neat idea for a programming puzzle. However, do they have any use beyond that?
30
votes
5answers
5k views

Champaign Fountain Puzzle

Empty glasses of water are arranged in the following order: When you pour liquid into the 1st glass if it's full, then the extra liquid would be flown into the glasses 2 and 3 in equal quantities. ...
0
votes
1answer
733 views

Puzzle solving: Minimum number of steps to achieve a goal

I have been doing some programming contest problems, and I have noticed that many of them involve something along the lines of "get the minimum number of steps necessary to achieve a certain goal". ...
52
votes
11answers
12k views

Get 100 highest numbers from an infinite list

One of my friend was asked this interview question - "There is a constant flow of numbers coming in from some infinite list of numbers out of which you need to maintain a datastructure as to ...
1
vote
2answers
246 views

What is a O(n) algorithm to solve this puzzle?

We are going to hold a meeting where everybody will speak in clockwise direction around a table. There are n people with n spots. Each person has a position preference (e.g. some want to go first, ...
9
votes
4answers
3k views

N queens, X by Y board decision problem interview question

I was asked the following question in an interview today and I've been thinking about it ever since. I was not able to answer it and haven't been able to find a solution online. Given a chess board ...
79
votes
15answers
45k views

Tricky logic puzzles - Are they really useful in assessing programming skills? [closed]

In the last interview I attended, I was asked to solve a puzzle where I was expected to measure exactly blah liters of water given two buckets with capacities - blah and blah liters respectively. I ...
4
votes
5answers
2k views

sets of numbers that sum to a certain number?

I was asked this in an interview, and I'm not sure what the answer is or how to approach the problem. Find a pair of numbers that sum up to zero (or any other number), then find three (and then ...
-2
votes
1answer
190 views

How does one generate challenging different puzzles like the one in AirLock android game [closed]

here's the link of the app: https://play.google.com/store/apps/details?id=com.iatll.airlock I had studied AI in the final year of b.tech cs programme, and i do remember some algorithm of ...
1
vote
1answer
671 views

Reading graph inputs for a programming puzzle and then solving it

I just took a programming competition question and I absolutely bombed it. I had trouble right at the beginning itself from reading the input set. The question was basically a variant of this puzzle ...
1
vote
3answers
868 views

Backtracking with Killer Sudoku

I'm developing a Killer Sudoku solver for a school project. I've programmed 10 human strategies showing what they are doing in order to be the most educational possible. It can solve hard Killer ...