freeCodeCamp/curriculum/challenges/english/10-coding-interview-prep/project-euler/problem-112-bouncy-numbers.english.md

id, challengeType, title, forumTopicId

id	challengeType	title	forumTopicId
5900f3dd1000cf542c50feef	5	Problem 112: Bouncy numbers	301738

Description

Working from left-to-right if no digit is exceeded by the digit to its left it is called an increasing number; for example, 134468. Similarly if no digit is exceeded by the digit to its right it is called a decreasing number; for example, 66420. We shall call a positive integer that is neither increasing nor decreasing a "bouncy" number; for example, 155349. Clearly there cannot be any bouncy numbers below one-hundred, but just over half of the numbers below one-thousand (525) are bouncy. In fact, the least number for which the proportion of bouncy numbers first reaches 50% is 538. Surprisingly, bouncy numbers become more and more common and by the time we reach 21780 the proportion of bouncy numbers is equal to 90%. Find the least number for which the proportion of bouncy numbers is exactly 99%.

Instructions

Tests

tests:
  - text: <code>euler112()</code> should return 1587000.
    testString: assert.strictEqual(euler112(), 1587000);

Challenge Seed

function euler112() {
  // Good luck!
  return true;
}

euler112();

Solution

// solution required