chore(i8n,learn): processed translations
This commit is contained in:
committed by
Mrugesh Mohapatra
parent
15047f2d90
commit
e5c44a3ae5
@ -0,0 +1,113 @@
|
||||
---
|
||||
id: 5900f3a31000cf542c50feb6
|
||||
title: 'Problem 55: Lychrel numbers'
|
||||
challengeType: 5
|
||||
forumTopicId: 302166
|
||||
dashedName: problem-55-lychrel-numbers
|
||||
---
|
||||
|
||||
# --description--
|
||||
|
||||
If we take 47, reverse and add, 47 + 74 = 121, which is palindromic.
|
||||
|
||||
Not all numbers produce palindromes so quickly. For example,
|
||||
|
||||
<div style="margin-left: 4em;">
|
||||
349 + 943 = 1292,<br>
|
||||
1292 + 2921 = 4213<br>
|
||||
4213 + 3124 = 7337<br>
|
||||
</div>
|
||||
|
||||
That is, 349 took three iterations to arrive at a palindrome.
|
||||
|
||||
Although no one has proved it yet, it is thought that some numbers, like 196, never produce a palindrome. A number that never forms a palindrome through the reverse and add process is called a Lychrel number. Due to the theoretical nature of these numbers, and for the purpose of this problem, we shall assume that a number is Lychrel until proven otherwise. In addition you are given that for every number below ten-thousand, it will either (i) become a palindrome in less than fifty iterations, or, (ii) no one, with all the computing power that exists, has managed so far to map it to a palindrome. In fact, 10677 is the first number to be shown to require over fifty iterations before producing a palindrome: 4668731596684224866951378664 (53 iterations, 28-digits).
|
||||
|
||||
Surprisingly, there are palindromic numbers that are themselves Lychrel numbers; the first example is 4994.
|
||||
|
||||
How many Lychrel numbers are there below `num`?
|
||||
|
||||
**Note:** Wording was modified slightly on 24 April 2007 to emphasize the theoretical nature of Lychrel numbers.
|
||||
|
||||
# --hints--
|
||||
|
||||
`countLychrelNumbers(1000)` should return a number.
|
||||
|
||||
```js
|
||||
assert(typeof countLychrelNumbers(1000) === 'number');
|
||||
```
|
||||
|
||||
`countLychrelNumbers(1000)` should return 13.
|
||||
|
||||
```js
|
||||
assert.strictEqual(countLychrelNumbers(1000), 13);
|
||||
```
|
||||
|
||||
`countLychrelNumbers(3243)` should return 39.
|
||||
|
||||
```js
|
||||
assert.strictEqual(countLychrelNumbers(3243), 39);
|
||||
```
|
||||
|
||||
`countLychrelNumbers(5000)` should return 76.
|
||||
|
||||
```js
|
||||
assert.strictEqual(countLychrelNumbers(5000), 76);
|
||||
```
|
||||
|
||||
`countLychrelNumbers(7654)` should return 140.
|
||||
|
||||
```js
|
||||
assert.strictEqual(countLychrelNumbers(7654), 140);
|
||||
```
|
||||
|
||||
`countLychrelNumbers(10000)` should return 249.
|
||||
|
||||
```js
|
||||
assert.strictEqual(countLychrelNumbers(10000), 249);
|
||||
```
|
||||
|
||||
# --seed--
|
||||
|
||||
## --seed-contents--
|
||||
|
||||
```js
|
||||
function countLychrelNumbers(num) {
|
||||
|
||||
return true;
|
||||
}
|
||||
|
||||
countLychrelNumbers(10000);
|
||||
```
|
||||
|
||||
# --solutions--
|
||||
|
||||
```js
|
||||
const countLychrelNumbers = (size) => {
|
||||
const numReverse = (num) => {
|
||||
return Number(num.toString().split('').reverse().join(''));
|
||||
};
|
||||
const isPalin = (num) => {
|
||||
if (numReverse(num) === num) {
|
||||
return true;
|
||||
}
|
||||
return false;
|
||||
};
|
||||
let total = 0;
|
||||
for (let i = 1; i < size; i++) {
|
||||
let loopCount = 1;
|
||||
let sum = i;
|
||||
while (loopCount < 50) {
|
||||
sum = sum + numReverse(sum);
|
||||
if (isPalin(sum)) {
|
||||
break;
|
||||
} else {
|
||||
loopCount++;
|
||||
}
|
||||
}
|
||||
if (loopCount === 50) {
|
||||
total++;
|
||||
}
|
||||
}
|
||||
return total;
|
||||
}
|
||||
```
|
Reference in New Issue
Block a user