Questions tagged [self-validating]

A restricted-source challenge where the task is to check the source restriction. This means when fed itself as input the program must output true.

Filter by
Sorted by
Tagged with
21 votes
8 answers
2k views

Do you win a Numeric Mahjong?

Background Numeric Mahjong is a hypothetical variation of Japanese Mahjong, played with nonnegative integers instead of Mahjong tiles. Given a list of nonnegative integers, it is a winning hand if it ...
Bubbler's user avatar
  • 73.8k
17 votes
9 answers
2k views

Exactly two neighbors

Given as input a list of positive integers, your task is to determine if every integer present has exactly two neighbors in the list. The neighbors of a integer \$x\$ are the distinct integers that ...
Wheat Wizard's user avatar
  • 96.5k
11 votes
3 answers
382 views

Unique rainbow programs

Given a list of positive integers as input you are to determine if there is a way to pair up the elements such that: All but one element is in a pair No element is in more than one pair Every pair is ...
Wheat Wizard's user avatar
  • 96.5k
20 votes
17 answers
2k views

Appearing a unique number of times

Your task is to write a program or function that takes as input a list of positive integers and determines if there are any two integers in the list, that both appear the same number of times. For ...
Wheat Wizard's user avatar
  • 96.5k
40 votes
12 answers
2k views

A well linked challenge

An activity I sometimes do when I'm bored is to write a couple of characters in matching pairs. I then draw lines (over the tops never below) to connect these characters. For example I might write \$...
Wheat Wizard's user avatar
  • 96.5k
23 votes
16 answers
3k views

A Semi-palindrome Puzzle

An palindrome is a word that is its own reverse. Now there are some words that might look like palindromes but are not. For example consider the word sheesh, <...
Wheat Wizard's user avatar
  • 96.5k
6 votes
6 answers
939 views

Lucas and Fibonacci are in pair

Influenced by Non-discriminating Programming, I made up an idea of a similar challenge. Here, we say a string is a Lucas string if the number of appearances of each character is a Lucas number (2, 1, ...
Shieru Asakoto's user avatar
19 votes
12 answers
2k views

In for a bumpy ride

Your task is to write a computer program or function that takes a list of nonnegative integers of at least length 2 and determines if they are a "zigzag". A sequence is a zigzag if and only ...
Wheat Wizard's user avatar
  • 96.5k
82 votes
41 answers
12k views

Non-discriminating Programming

We say a string is non-discriminating if each of the string's characters appears the same number of times and at least twice. Examples "aa!1 1 !a !1" is non-...
Laikoni's user avatar
  • 26.1k