2.0 KiB
2.0 KiB
id | title | challengeType | forumTopicId | dashedName |
---|---|---|---|---|
5900f36e1000cf542c50fe81 | Problem 2: Even Fibonacci Numbers | 5 | 301838 | problem-2-even-fibonacci-numbers |
--description--
Each new term in the Fibonacci sequence is generated by adding the previous two terms. By starting with 1 and 2, the first 10 terms will be:
1, 2, 3, 5, 8, 13, 21, 34, 55, 89, ...
By considering the terms in the Fibonacci sequence whose values do not exceed n
, find the sum of the even-valued terms.
--hints--
fiboEvenSum(10)
should return a number.
assert(typeof fiboEvenSum(10) === 'number');
Your function should return an even
value.
assert.equal(fiboEvenSum(10) % 2 === 0, true);
Your function should sum the even-valued Fibonacci numbers: fiboEvenSum(8)
should return 10.
assert.strictEqual(fiboEvenSum(8), 10);
fiboEvenSum(10)
should return 10.
assert.strictEqual(fiboEvenSum(10), 10);
fiboEvenSum(34)
should return 44.
assert.strictEqual(fiboEvenSum(34), 44);
fiboEvenSum(60)
should return 44.
assert.strictEqual(fiboEvenSum(60), 44);
fiboEvenSum(1000)
should return 798.
assert.strictEqual(fiboEvenSum(1000), 798);
fiboEvenSum(100000)
should return 60696.
assert.strictEqual(fiboEvenSum(100000), 60696);
fiboEvenSum(4000000)
should return 4613732.
assert.strictEqual(fiboEvenSum(4000000), 4613732);
--seed--
--seed-contents--
function fiboEvenSum(n) {
return true;
}
--solutions--
const fiboEvenSum = (number) => {
if (number <= 1) {
return 0;
} else {
let evenSum = 0,
prevFibNum = 1,
fibNum = 2; // According to problem description our Fibonacci series starts with 1, 2
for (let i = 2; fibNum <= number; i++) {
if (fibNum % 2 == 0) {
evenSum += fibNum;
}
[prevFibNum, fibNum] = [fibNum, prevFibNum + fibNum];
}
return evenSum;
}
};