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.

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76 votes
37 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-...
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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 \$...
  • 90.4k
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 ...
  • 90.4k
23 votes
16 answers
2k 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, <...
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