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First 10 Fibonacci numbers are 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. (#34723)

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Rohan Mohammad
2019-01-25 12:21:45 +05:30
committed by Kristofer Koishigawa
parent f2c63979ef
commit 66688e8a02
1 changed files with 6 additions and 6 deletions
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guide/english/certifications/coding-interview-prep/project-euler/problem-2-even-fibonacci-numbers/index.md
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@@ -8,10 +8,10 @@ title: Even Fibonacci Numbers
- In this challenge we have to sum all the even numbers upto `nth` term in the sequence. - In this challenge we have to sum all the even numbers upto `nth` term in the sequence.
- Example for `fiboEvenSum(10)`: - Example for `fiboEvenSum(10)`:
+ The sequence till 10th term is: + The sequence till 10th term is:
1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144 1, 2, 3, 5, 8, 13, 21, 34, 55, 89
+ Sum of all even number in the above sequence is: + Sum of all even number in the above sequence is:
2 + 8 + 34 + 144 = 188 2 + 8 + 34 = 44
### Solution: ### Solution:
@@ -20,7 +20,7 @@ title: Even Fibonacci Numbers
function fiboEvenSum(n) { function fiboEvenSum(n) {
let first = 1, second = 2, sum = 2, fibNum; // declaring and initializing variables let first = 1, second = 2, sum = 2, fibNum; // declaring and initializing variables
if (n <= 1) return sum; // edge case if (n <= 1) return sum; // edge case
for (let i = 2; i <= n; i++){ // looping till n for (let i = 3; i <= n; i++){ // looping till n
fibNum = first + second; // getting the ith fibonacci number fibNum = first + second; // getting the ith fibonacci number
first = second; first = second;
second = fibNum; second = fibNum;
@@ -33,8 +33,8 @@ function fiboEvenSum(n) {
```js ```js
// We use memoization technique to save ith fibonacci number to the fib array // We use memoization technique to save ith fibonacci number to the fib array
function fiboEvenSum(n){ function fiboEvenSum(n){
const fib = [1, 2]; const fib = [1, 1, 2];
let sumEven = fib[1]; let sumEven = fib[2];
function fibonacci(n){ function fibonacci(n){
if (n <= 1) return fib[n]; // base condition if (n <= 1) return fib[n]; // base condition
else if (fib[n]) return fib[n]; // if the number exists in the array we cache it and return else if (fib[n]) return fib[n]; // if the number exists in the array we cache it and return
@@ -48,6 +48,6 @@ function fiboEvenSum(n){
return sumEven; return sumEven;
} }
``` ```
- [Run Code](https://repl.it/@ezioda004/Project-Euler-Problem-2-Even-Fibonacci-Numbers) - [Run Code](https://repl.it/@scissorsneedfoo/Project-Euler-Problem-2-Even-Fibonacci-Numbers)
### References: ### References:
- [Wikipedia](https://en.wikipedia.org/wiki/Fibonacci_number) - [Wikipedia](https://en.wikipedia.org/wiki/Fibonacci_number)