Implement merge sort.js

// Takes in an array that has two sorted subarrays,
//  from [p..q] and [q+1..r], and merges the array
var merge = function(array, p, q, r) {
    // This code has been purposefully obfuscated,
    //  as you'll write it yourself in next challenge.
    var a=[],b=[],c=p,d,e;for(d=0;c<=q;d++,c++){a[d]=array[c];}for(e=0;c<=r;e++,c++){b[e]=array[c];}c=p;for(e=d=0;d<a.length&&e<b.length;){if(a[d]<b[e]){array[c]=a[d];d++;} else {array[c]=b[e]; e++;}c++; }for(;d<a.length;){array[c]=a[d];d++;c++;}for(;e<b.length;){array[c]=b[e];e++;c++;}
};


// Takes in an array and recursively merge sorts it
var mergeSort = function(array, p, r) {
    if (p < r){
        var q = floor((p+r)/2);
        mergeSort(array, p, q);
        mergeSort(array, q+1, r);
        merge(array, p, q, r);
    }
};

var array = [14, 7, 3, 12, 9, 11, 6, 2];
mergeSort(array, 0, array.length-1);
println("Array after sorting: " + array);
Program.assertEqual(array, [2, 3, 6, 7, 9, 11, 12, 14]);

var array2 = [0, 14, -10, 8, 12, 6, 7, 40];
mergeSort(array2, 0, array2.length-1);
Program.assertEqual(array2, [-10, 0, 6, 7, 8, 12, 14, 40]);