Euler08.js

/*
The four adjacent digits in the 1000-digit number that have the greatest product are 9 × 9 × 8 × 9 = 5832.

73167176531330624919225119674426574742355349194934
96983520312774506326239578318016984801869478851843
85861560789112949495459501737958331952853208805511
12540698747158523863050715693290963295227443043557
66896648950445244523161731856403098711121722383113
62229893423380308135336276614282806444486645238749
30358907296290491560440772390713810515859307960866
70172427121883998797908792274921901699720888093776
65727333001053367881220235421809751254540594752243
52584907711670556013604839586446706324415722155397
53697817977846174064955149290862569321978468622482
83972241375657056057490261407972968652414535100474
82166370484403199890008895243450658541227588666881
16427171479924442928230863465674813919123162824586
17866458359124566529476545682848912883142607690042
24219022671055626321111109370544217506941658960408
07198403850962455444362981230987879927244284909188
84580156166097919133875499200524063689912560717606
05886116467109405077541002256983155200055935729725
71636269561882670428252483600823257530420752963450

Find the thirteen adjacent digits in the 1000-digit number that have the greatest product. What is the value of this product?
*/

let digits = [
'73167176531330624919225119674426574742355349194934',
'96983520312774506326239578318016984801869478851843',
'85861560789112949495459501737958331952853208805511',
'12540698747158523863050715693290963295227443043557',
'66896648950445244523161731856403098711121722383113',
'62229893423380308135336276614282806444486645238749',
'30358907296290491560440772390713810515859307960866',
'70172427121883998797908792274921901699720888093776',
'65727333001053367881220235421809751254540594752243',
'52584907711670556013604839586446706324415722155397',
'53697817977846174064955149290862569321978468622482',
'83972241375657056057490261407972968652414535100474',
'82166370484403199890008895243450658541227588666881',
'16427171479924442928230863465674813919123162824586',
'17866458359124566529476545682848912883142607690042',
'24219022671055626321111109370544217506941658960408',
'07198403850962455444362981230987879927244284909188',
'84580156166097919133875499200524063689912560717606',
'05886116467109405077541002256983155200055935729725',
'71636269561882670428252483600823257530420752963450',
].join('');

function problem8() {
    let sequenceLength = 13;
    let number = digits;
    let highestProduct = 0;
    let firstIndex = 0;
    let endIndex = firstIndex + sequenceLength;
    
    while (endIndex != number.length) {
        let subString = number.substring(firstIndex, endIndex);
        let array = subString.split('');
        let product = 1;
        
        for (var i = 0; i < array.length; i++) {
            product = product * array[i];
        }
        
        if (product > highestProduct) {
            highestProduct = product;
        }

        firstIndex = firstIndex + 1;
        endIndex = firstIndex + sequenceLength;
    }
    console.log("The largest product is: " + highestProduct);
}

problem8();