index.html

﻿<!doctype html>
<html>
    <head>
        <meta charset="utf-8">
        <title>Assignment</title>
    </head>
    <body>

		<script type="text/javascript">

			var debug = 1;

			function out(st) {

				document.write('<p>'+ st + '</p>');

				try {
					if (debug)
						console.log(st);
				} catch(e) {}
			}

            function generateRandomArray(n) {

                var arr = [];

                for (var i=0; i < n; i ++) {
                    arr.push(Math.floor( Math.random() * n + n));
                }

                return arr.sort();
            }

            /**
             * Merge all elements in a and b, sorted in descending order.
             *
             * @param {Array}, {Array} source arrays to merge and sort
             * @return {Array} resulting merged array
            */
            function mergeAndReorder(a, b) {

                var result = [];

                while ((a.length != 0) && (b.length != 0)) {
                    if (a[a.length - 1] >= b[b.length - 1]) {
                        result.push(a.pop());
                    } else {
                        result.push(b.pop());
                    }
                }

				while (a.length != 0) {
					result.push( a.pop());
				}

				while (b.length != 0) {
					result.push( b.pop());
				}

                return result;
            }

			/**
             * Run a test to join the arrays using build in methods and the assignment method.
			 * Display output (if not too large) and execution times, finally are the results
			 * as expected.
             *
             * @param {String}, {Array}, {Array} Title and the two source arrays
            */
			function test(title, a, b) {
				out(title);

				if (a.length < 50)
					out('a: '+ a);

				if (b.length < 50)
					out('b: '+ b);

				var t0 = performance.now();
				var z = a.concat(b).sort(function(a, b){return b-a});

				if (z.length < 50)
					out(z);

				var t1 = performance.now();
				out('concat-sort: '+ (t1 - t0).toFixed(4) +'ms');

				t0 = performance.now();

				var result = mergeAndReorder(a, b)
				if (result.length < 50)
					out(result);

				t1 = performance.now();

				out('assignment:'+ (t1 - t0).toFixed(4) +'ms');

				out('Equals: '+ (JSON.stringify(z) === JSON.stringify(result)) );
			}

        var a = [1, 3, 5, 7, 9]
            ,b = [2, 4, 6, 8, 10];

		var n = 50
			,c = generateRandomArray(n)
			,d = generateRandomArray(n)


		test('Simple', a, b);
		test('Long ('+ n +')', c, d);

        </script>
    </body>
</html>