Euler Problem 26

by Andrew Poes

HTML

<!-- A unit fraction contains 1 in the numerator. The decimal representation of the unit fractions with denominators 2 to 10 are given:

1/2	= 	0.5
1/3	= 	0.(3)
1/4	= 	0.25
1/5	= 	0.2
1/6	= 	0.1(6)
1/7	= 	0.(142857)
1/8	= 	0.125
1/9	= 	0.(1)
1/10	= 	0.1
Where 0.1(6) means 0.166666..., and has a 1-digit recurring cycle. It can be seen that 1/7 has a 6-digit recurring cycle.

Find the value of d < 1000 for which 1/d contains the longest recurring cycle in its decimal fraction part. -->

CSS

.print {
    position: relative;
    display: inline-block;
    background-color: black;
    color: white;
    font-family: Helvetica, Helvetica-Neue, sans-serif;
    font-weight: bold;
    font-size: 24px;
    letter-spacing: -1.5px;
    padding: 4px 8px;
}

body {
    background-color: #eeeeee;
}
}

input {
    padding: 20px;
}
}

JavaScript

$(document).ready(function() {
    var longest = 0;
    var longestIndex = 0;
    for (var i = 0; i < 1000; ++i) {
        var len = lengthOfRepeat(i);
        if (longest < len) {
            longestIndex = i;
            longest = len;
        }
    }
    print(longest, longestIndex);
})

function lengthOfRepeat(n) {
    var value = 1;
    var arr = []
    while (value) {
        value *= 10;
        value %= n;
        var ffound = arr.indexOf(value);
        if (ffound >= 0) {
            return arr.length - ffound;
        }
        arr.push(value)
    }
    return 0;
}

function print() {
    var args = Array.prototype.slice.apply(arguments)
    var str = ""
    for (arg of args) {
        str += arg + ", "
    }
    str = str.substring(0, str.length - 2)
    var el = newel(str)
    $("body").append(el)
    $("body").append("</br>")
}

function newel(str) {
    var el = document.createElement("div")
    $(el).html(str)
    $(el).addClass("print")
    return el
}