# All Questions

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### Physics golf: inclined shooting

"And now for something, completely different." An angry bird is shot at an angle β to the horizontal at a speed u. The ground is steep, inclined at an angle α. Find the horizontal distance q that the ...
4k views

### Carmichael Numbers

EDIT: I am changing the challenge. Write a program to print Carmichael numbers. The challenge is to print the maximum number of them in less than 5 secs. The numbers should be in increasing order. ...
3k views

### Square free Numbers

Given a number N, write the shortest complete program to find the number of square-free integers below N. Sample Input 100000 Sample Output 60794 Constraints: ...
981 views

### Crossword grid verification

Validate a proposed crossword grid. Entries should be full programs that simply test a proposed grid to determine if it meets a set of conditions for making crossword solvers happy. Input The input ...
893 views

### Comparing powers.

Compare two numbers N1 = abc, N2 = def by constructing a function f(a,b,c,d,e,f) that: returns 1 if N1 > N2 returns -1 if N1 < N2 Note: You are not required to return any value for any other ...
288 views

### Power modulo golf. [closed]

Write a function f(a,b,c) that calculates a^b (mod c) in less than 10 seconds. a, b < 10^100 c < 10000. examples: ...
887 views

### Modulo code golf

Write a function f(a,b) that returns a mod b given the constraints: you can't use division in any way ...
985 views

### Finding "sub-palindromes" 2: subsequences.

The same task as Finding "sub-palindromes" but instead of finding substrings you must find subsequences that are not substrings. eg1: ...
5k views

### Print a Binary Tree

Inspired by a recent question on SO... Write a function to print a binary tree in the following format: 3 / \ 1 5 \ / \ 2 4 6 The output should ...
699 views

### Implement BCD Arithmetic

Write the shortest function you can that takes two binary-coded decimal integers and a character indicating an arithmetic operation to perform and return the result. Input Specification You will be ...
2k views

### Polynomial Long Division

Implement polynomial long division, an algorithm that divides two polynomials and gets the quotient and remainder: (12x^3 - 5x^2 + 3x - 1) / (x^2 - 5) = 12x - 5 R 63x - 26 In your programs, you will ...
1k views

Another problem from our internal golfing...this one around the holidays last year. PROBLEM Andy, Barb, Carl, Didi, Earl, and Fran are buying gifts for each other. Draw names for a gift exchange. ...
685 views

### How many squares are guarded by chess queens?

Today marks the 15th anniversary of Garry Kasparov's defeat against Deep Blue. Speaking of chess... Input is a string that represents an 8x8 chess board containing only empty squares (...
4k views

### Fair outcome using unfair coin [closed]

I have been thinking a lot about the following puzzle, but could not arrive at a solution. Can someone explain to me how can you get a fair (equal probability) outcome using only an unfair coin (...
3k views

### Partition of a positive integer N [closed]

Find the number of partitions of a positive integer n. Hope someone uses the explicit finite formula for the partition function defined in Jan Hendrik Brunier and Ken Ono paper here. ...
1k views

### Random Sentence Generator

Write the shortest program you can in any language that reads a context-free grammar from and the number of sentences to produce from stdin, and generates that many ...
524 views

### Is this figure connected?

You are given a list of (x,y) grid coordinates. Your function should decide whether the figure obtained by coloring in the squares of the grid with the given ...
3k views

### Roman numeral converter function

Create the shortest function to convert a string of Roman numerals to an integer. The rules for each letter can be found at the Wikipedia page. Letters above 1,000 will have parentheses placed ...
8k views

### Print NxN spiral of ascending numbers [closed]

The numbers should be printed with leading zeroes in a field with length = (number of digits of N^2). Input (N): 4 Output: ...
689 views

### Finish a symmetrical map

You are given one-quarter of a map that is symmetrical over the x- and y-axes as input. The program should print the complete map. The map can contain the following characters: ...
4k views

### Calculate the last digits of Graham's Number

Graham's number ends in a 7. It is a massive number, in theory requiring more information to store than the size of the universe itself. However it is possible to calculate the last few digits of ...
1k views

### Sum of integers in string, separated by non-numericals such as 'a' and 'Y'

Create a program which sums all integers found in a string which is set as a variable in the program (thus, the program doesn't have to handle any input). The integer numbers are separated by non-...
1k views

### Calculate the number of trailing zeros in n! [duplicate]

Write a function which takes n as a parameter, and returns the number of trailing zeros in n!. Input Constraints 0 <= n <= 10^100 Output Constraints Should be return the result in less than ...
6k views

### Binary representation of a number is palindrome or not?

Write a full program to find whether the binary representation of a number is palindrome or not? Sample Input 5 Sample Output YES Print ...
1k views

### ->The Tragedy of Macbeth<- [closed]

The Setup Here you can find the full text of The Tragedy of Macbeth. If you view the source, and save it as text, you will notice it comes out to 206,244 total characters (including the whitespace ...
4k views

### Last non-zero digit of n!

Given an integer 1 ≤ N ≤ 1,000,000 as input, output the last non-zero digit of N!, where ! is the factorial (the product of all numbers from 1 to N, inclusive). This is OEIS sequence A008904. Your ...
890 views

### Word Spinner Puzzle

This is a word puzzle. Your program should accept two words on the standard input. Word one is the start word. Word two is the end word. From the start word you have to reach the end word changing/...
904 views

### How much snow did you get?

My apologies for the wordiness. We had fun with it at work in our internal golfing, but it required a few emails for clarification, so I hope I captured most of that the first time. PROBLEM Given a “...
4k views

### Decipher a Vigenère ciphertext

The Vigenère cipher was a simple polyalphabetic cipher that basically applied one of several Caesar ciphers, according to a key. Bascially the letters in the key indicate which shifted alphabet to use....
1k views

### Find prime factors [duplicate]

A whole program to find the prime factors of a given number. The number will be given on standard input.
3k views

### Multiply without multiply [closed]

Write the fastest (best big-O) and smallest multiplication algorithm for positive integers, without using multiplication operators. You are only allowed addition, subtraction, logical functions (AND, ...
591 views

1k views

### Tree traversal: Depth-first search

Write the shortest code that traverses a tree, depth-first. Input Any programmatical structure found in your language of choice: lists, tuples, queues etc. Output A list of "names" of the nodes in ...
5k views

### Robot Finds Kitten

The challenge The shortest code by character count to help Robot find kitten in the fewest steps possible. Golfers, this is a time of crisis - Kitten gone missing and it's Robot's job to find it! ...
4k views

### Self-Interpreting Interpreter

Based on a comment by George Edison to this question, write the smallest self-interpreting interpreter. You may use the language of your choosing. Empty languages do not count. Your program must be ...
6k views

### Assembly Language Quine

Write the shortest possible assembly-language quine. Use any ISA you want, unless it has a print-quine instruction or equivalent. Examples include x86, MIPS, ...
4k views

### Basic Calculator

You must write a program to evaluate a string that would be entered into a calculator. The program must accept input and output the correct answer. For languages that do not have standard input/...
610 views

### Perfect powers in more than one way?

Challenge Your task is to write a program or function which, given a positive integer $N$, finds all positive integers less than or equal to $N$ that can be expressed as a perfect power in more ...
1k views

### Fix a broken random function

A friend has an add-on card in their computer which generates a perfectly random number from 1 to 5 inclusive. Unfortunately, they spilt cola on it somehow, and it now generates only 2's for all ...
705 views

### Integer to string with given radix

Write the shortest function to convert an integer into a numeric representation given a radix between 2 and 62. e.g.: to_string(351837066319, 31) => "codegolf"
428 views

### Minimum of last k

Write a function that takes two arguments: a number k and a list l, and that returns another list ...
117 views

### Five aligned points and some of the pairwise distances. Infer the relative positions! [closed]

Given five points on a straight line such that their pairwise distances are 1,2,4, ..., 14,18,20 (after ordering), find the respective positions of the five points (relative to the furthest point on ...