Questions tagged [string]

A competition to solve a particular problem through the usage and manipulation of strings.

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4 votes
13 answers

Find The Least Common Characters

Given a string, find the 10 least common alpha-numeric characters within that string. Output should be formatted with numbers left-padded with spaces so they look like this: ...
  • 4,274
6 votes
12 answers

Ode-cay Olf-gay

Write a program which accepts a sentence into stdin, and writes that sentence to stdout in pig latin. Here are some test cases which your program should handle: ...
  • 1,205
-8 votes
2 answers

Implementing a Traffic Light Checker [closed]

A three-color traffic light must switch lights in the following order: red, green, yellow, red. To indicate when crossing slowly without a stop is permitted, the yellow signal may be flashed. To ...
  • 101
1 vote
2 answers

Storing a DNS name as compactly as possible in memory (preferably in C#) [closed]

What is the most compact way to encode/save DNS names in memory? For example, storing "" as a string in .NET will result in the object being encoded as UTF-16, and it will consume twice ...
34 votes
6 answers

Balance chemical equations!

Bernd is a high school student who has some problems in chemistry. In class he has to design chemical equations for some experiments they are doing, such as the combustion of heptane ...
  • 10k
12 votes
27 answers

Removing unique elements from string

I came upon this question, because it seems to be very common use-case to find unique characters in string. But what if we want to get rid of them? Input contains only lower case alphabets. Only ...
  • 239
15 votes
28 answers

Shorten text with Run Length Encoding

Shorten (or not) text using run length encoding Input: heeeello woooorld Output: 1h4e2l1o 1w4o1r1l1d Read lines from stdin. Print to stdout. Stderr is of course discarded. Assume there are ...
  • 1,508
19 votes
30 answers

Print custom alphabet

The Challenge Display the alphabet from a given letter read from console input. If the letter is uppercase, you have to display the alphabet uppercased. The alphabet printed must end in the precedent ...
  • 4,077
5 votes
7 answers

Finding variables in code

Given some code in your language as a string, find and display all the variable names. Examples in pseudocode: ...
  • 4,274
5 votes
6 answers

Detecting loops in in in strings

Given a string, mark which parts in the string repeat in box brackets, and write how many times it does so before the box. Example:st st st Hello ThereThere ...
  • 4,274
25 votes
17 answers

Topographic Strings

Here is some example input, so I can explain what the problem is: ((1 2)(3 (4 5) moo)) (i (lik(cherries)e (woohoo))) Think of this line of text as a topographic ...
  • 4,274
13 votes
31 answers

Remove vowels without using too many different characters

The challenge is to remove vowels (a, e, i, o, u) from string from STDIN (yes, I know, simple). You can expect that your program will be not ran with any arguments in ...
73 votes
119 answers

Print the alphabet without using each vowel

Inspiration: in 1939, a man named Ernest Vincent Wright wrote a novel called Gadsby without using the letter 'e'. Your task is to write a set of (up to 5) programs in any language (which has a text-...
  • 1,231
27 votes
66 answers

Is string X a subsequence of string Y?

Given strings X and Y, determine whether X is a subsequence of Y. The empty string is regarded as a subsequence of every string. (E.g., '' and ...
  • 3,042
17 votes
11 answers

Find the minimum edit distance between two strings

Explanation The edit distance between two strings is a function of the minimum possible number of insertions, deletions, or substitutions to convert one word into another word. Insertions and ...
  • 7,702
2 votes
3 answers

all occurences of each line from a file in another file for each line in the first file

This is a code golf problem: Say you have two files, one file s and one file h. The problem is that for each line l of s you should produce a list that contains all lines of h that contain l. By "...
  • 121
5 votes
4 answers

Implement Oplop

Oplop is an algorithm to generate website specific passwords based on a master password and a keyword. It is described here: There's an online ...
  • 4,365
11 votes
8 answers

ASCII ruler generation

The challenge is to generate an ASCII character count ruler in the following format: ...
-2 votes
2 answers

Conversion to palindrome with minimal points used

Input: a word (2-100 characters) Convert this word to a palindrome: delete character - 13 points add character - 12 points increase character - 5 points ('d' > 'e') decrease character - 4 points ('n'...
  • 123
7 votes
1 answer

String manipulation

The challenge is to manipulate strings using basic Vim-like commands Input: A string of text to be transformed. The input alphabet is [a-z]. A string of legal commands Output: The transformed ...
  • 1,249
53 votes
49 answers

Outputting ordinal numbers (1st, 2nd, 3rd)

I would like to generate (as a return result of a function, or simply as the output of a program) the ordinal suffix of a positive integer concatenated to the number. Samples: ...
  • 633
22 votes
24 answers

Find columns where all characters are the same

I came across this question on SO and thought it'd make a nice golf challenge. So here it is: Challenge: Write a program that reads a sequence of character strings, one per line, and outputs a list ...
21 votes
9 answers

Generating PBM bitmap files from ASCII text

The PBM (Portable BitMap) format is a very simple ASCII black and white bitmap format. Here's an example for the letter 'J' (copy-pasted from the wikipedia link): P1 # This is an example bitmap of ...
  • 1,679
4 votes
14 answers

Write the shortest code to match a tail-repeating string where one character falls off the head in each repetition

In this code-golf, you will attempt to match a string that is tail-repeating with one character falling off the head on each iteration. The code needs to be able to accept a string, and return to the ...
-7 votes
8 answers

Smple way to get min & max

You will take a set of input numbers, and output the minimum and maximum of the set. You can either write two programs, with 1 program doing each function, or one combined program. Here's an example ...
11 votes
9 answers

Check if a string is a shuffle of twins

Explanation Two strings can be shuffled by interspersing their letters to form a new string, much like two piles of cards can be shuffled to form a single pile. For example, the strings ...
  • 7,702
4 votes
2 answers

Decompose a String

Challenge You are to write the shortest complete program that takes a string as input from STDIN and decomposes it as far as possible, and prints the composition to STDOUT. To decompose a string, ...
  • 28.8k
15 votes
9 answers

Write a function that returns past tense of given verb

Challenge Write a function which takes an argument which is a verb, and returns the past tense of the verb. (Assume that the verb is regular) Past tense Note: consider y as neither consonant nor ...
  • 3,432
9 votes
7 answers

Program to Spoonerise words [duplicate]

A spoonerisation is swapping the first letter/pronounceable syllable of two or more words. Example: A lack of pies = A pack of lies. Bad salad = Sad ballad (ish) :) Challenge: Write a program to ...
57 votes
75 answers

How to randomize letters in a word

According to some controversial story, the odrer of ltteres in a wrod deos not mttaer much for raednig, as lnog as the frist and lsat lteter macth with the orignial wrod. So, for fun, what would be ...
  • 921
13 votes
9 answers

Soundex function

Write the shortest function to generate the American Soundex code for a surname only containing the uppercase letters A-Z. Your function must produce output consistent with all the linked page's ...
  • 5,567
17 votes
17 answers

Indent a string using given parentheses

Given the following input to the program: List of block start characters List of block end characters A string to format format the string with the blocks delimited by the two character sets ...
10 votes
5 answers

Simple Tag Parser

This is a model of a forgiving HTML parser. Instead of parsing HTML and extracting attributes, in this code golf, the tag parser will be simple. Write a function that parses a tag structure and ...
  • 5,921
48 votes
79 answers

Answer to life, the universe, and everything

Task Given a String as input, your task is to output 42 only if the input String happens to be exactly the following : ...
  • 1,945
21 votes
46 answers

Detect rotated strings

Read two strings from stdin. Output Yes if one string is a rotated version of the other. Otherwise output ...
  • 15k
91 votes
158 answers

Determine whether strings are anagrams

Challenge Given two strings, work out if they both have exactly the same characters in them. Example Input word, wrdo This returns true because they are the ...
  • 1,219
-3 votes
9 answers

Mixed up output [duplicate]

Write a function or program that outputs the following lines <input> time: ...
  • 5,428
8 votes
1 answer

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 ...
  • 2,042
12 votes
15 answers

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: ...
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18 votes
37 answers

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-...
  • 481
24 votes
20 answers

Chris Pine's "Deaf Grandma"

I'm a mentor at RubyLearning and one of the exercises we give to our students is the "Deaf Grandma" exercise from Chris Pine's book "Learn to Program". Here's the description: Write a Deaf Grandma ...
65 votes
130 answers

Reverse stdin and place on stdout

Requirements: Take an input on stdin including new lines / carriage returns of unlimited length (only bounded by system memory; that is, there is no inherent limit in the program.) Output the reverse ...
  • 3,292
25 votes
35 answers

Finding "sub-palindromes".

The shortest code that finds all unique "sub-palindromes" of a string, that is: any substring with length > 1 that is a palindrome. eg.1 ...
  • 5,428

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