The problem
This is problem 2 from the Project Euler.
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 that do not exceed the nth term, find the sum of the even-valued terms.
Let's begin
Initialise variables and common functions:
var test_values = [10, 18, 23, 43]; // list of numbers we wanna test // this function execute the code and records the time to execute function run_function(func, test_values) { for(var i in test_values){ console.log('Test value:', test_values[i]); var t0 = performance.now(); console.log('Output:', func(test_values[i])); var t1 = performance.now(); console.log("Took " + (t1 - t0) + " milliseconds."); console.log(); } } Attempt #1: recursive functions
The recursive way...
function fiboEvenSum(n) { var fib_nums = [1, 2]; fib_nums = add(n, fib_nums); var sum = 0; for(var i in fib_nums){ if(fib_nums[i]%2===0){ sum = sum + fib_nums[i] } } return sum; } function add(n, fib_nums){ var c = fib_nums[fib_nums.length-1] + fib_nums[fib_nums.length-2]; fib_nums.push(c); if(fib_nums.length<n){ return add(n, fib_nums); }else{ return fib_nums; } } run_function(fiboEvenSum, test_values); The output:
Test value: 10 Output: 44 Took 0.13000000035390258 milliseconds. Test value: 18 Output: 3382 Took 0.05999999848427251 milliseconds. Test value: 23 Output: 60696 Took 0.1049999991664663 milliseconds. Test value: 43 Output: 350704366 Took 0.08000000525498763 milliseconds. Here's my solution, can it be any better?
This is my Project Euler Challenge journey; anyone wants to do this together? It will be fun and we can learn a thing or two by solving this problem in different ways.
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