6cfd0fc503
* fix: improve Project Euler descriptions and test case Improve formatting of Project Euler test descriptions. Also add poker hands array and new test case for problem 54 * feat: add typeof tests and gave functions proper names for first 100 challenges * fix: continue fixing test descriptions and adding "before test" sections * fix: address review comments * fix: adjust grids in 18 and 67 and fix some text that reference files rather than the given arrays * fix: implement bug fixes and improvements from review * fix: remove console.log statements from seed and solution
2.0 KiB
2.0 KiB
id, challengeType, title, forumTopicId
| id | challengeType | title | forumTopicId |
|---|---|---|---|
| 5900f3721000cf542c50fe85 | 5 | Problem 6: Sum square difference | 302171 |
Description
The sum of the squares of the first ten natural numbers is,
12 + 22 + ... + 102 = 385
The square of the sum of the first ten natural numbers is,
(1 + 2 + ... + 10)2 = 552 = 3025
Hence the difference between the sum of the squares of the first ten natural numbers and the square of the sum is 3025 − 385 = 2640.
Find the difference between the sum of the squares of the first n natural numbers and the square of the sum.
Instructions
Tests
tests:
- text: <code>sumSquareDifference(10)</code> should return a number.
testString: assert(typeof sumSquareDifference(10) === 'number');
- text: <code>sumSquareDifference(10)</code> should return 2640.
testString: assert.strictEqual(sumSquareDifference(10), 2640);
- text: <code>sumSquareDifference(20)</code> should return 41230.
testString: assert.strictEqual(sumSquareDifference(20), 41230);
- text: <code>sumSquareDifference(100)</code> should return 25164150.
testString: assert.strictEqual(sumSquareDifference(100), 25164150);
Challenge Seed
function sumSquareDifference(n) {
// Good luck!
return true;
}
sumSquareDifference(100);
Solution
const sumSquareDifference = (number)=>{
let squareOfSum = Math.pow(sumOfArithmeticSeries(1,1,number),2);
let sumOfSquare = sumOfSquareOfNumbers(number);
return squareOfSum - sumOfSquare;
}
function sumOfArithmeticSeries(a,d,n){
return (n/2)*(2*a+(n-1)*d);
}
function sumOfSquareOfNumbers(n){
return (n*(n+1)*(2*n+1))/6;
}