matlockx/Combinations

## Combinations
<html>
<body>
<h1 id="title">Combinations</h1>

<input type="text" id="numbers" value="1,2,3,4,5" />
<input type="text" id="stars" value="1,2,3" />
<input type="submit" id="byBtn" value="Change" onclick="change()" />
<div id="info"></div>
<div id="combinations"></div>
<script>
function change() {

    var numbers = document.getElementById('numbers').value.split(",");
    var stars = document.getElementById('stars').value.split(",");

    var c = document.getElementById('combinations');
    var info = document.getElementById('info');
    var myTable = "<table border='1'><tr><td>Numbers</td><td>Stars</td></tr>";

    var start = performance.now();
    var numberCombinations = combinations(numbers.sort(), 5);
    var starCombinations = combinations(stars.sort(), 2);

    for (var i = 0; i < numberCombinations.length; i++) {
        for (var j = 0; j < starCombinations.length; j++) {
            myTable += "<tr><td>" +numberCombinations[i] + "</td><td>" + starCombinations[j] + "</td></tr>";
        }
    }
    info.innerHTML = "<br><br>Combinations: " + (numberCombinations.length * starCombinations.length) + "<br>" + logTime(start) + "<br><br>";
    c.innerHTML = myTable + "</table>";

}

function logTime(start) {
    var end = performance.now();
    var time = end - start;
    return 'Execution time: ' + time + ' ms';
}

function combinations(set, k) {
    var i, j, combs, head, tailcombs;

    if (!set || !k || k > set.length || k <= 0) {
        return [];
    }

    if (k == set.length) {
        return [set];
    }

    if (k == 1) {
        combs = [];
        for (i = 0; i < set.length; i++) {
            combs.push([set[i]]);
        }
        return combs;
    }
    combs = [];
    for (i = 0; i < set.length - k + 1; i++) {
        head = set.slice(i, i + 1);
        tailcombs = combinations(set.slice(i + 1), k - 1);
        for (j = 0; j < tailcombs.length; j++) {
            combs.push(head.concat(tailcombs[j]));
        }
    }
    return combs;
}
</script>
</body>
</html>
	<html>
	<body>
	<h1 id="title">Combinations</h1>

	<input type="text" id="numbers" value="1,2,3,4,5" />
	<input type="text" id="stars" value="1,2,3" />
	<input type="submit" id="byBtn" value="Change" onclick="change()" />
	<div id="info"></div>
	<div id="combinations"></div>
	<script>
	function change() {

	var numbers = document.getElementById('numbers').value.split(",");
	var stars = document.getElementById('stars').value.split(",");

	var c = document.getElementById('combinations');
	var info = document.getElementById('info');
	var myTable = "<table border='1'><tr><td>Numbers</td><td>Stars</td></tr>";

	var start = performance.now();
	var numberCombinations = combinations(numbers.sort(), 5);
	var starCombinations = combinations(stars.sort(), 2);

	for (var i = 0; i < numberCombinations.length; i++) {
	for (var j = 0; j < starCombinations.length; j++) {
	myTable += "<tr><td>" +numberCombinations[i] + "</td><td>" + starCombinations[j] + "</td></tr>";
	}
	}
	info.innerHTML = "<br><br>Combinations: " + (numberCombinations.length * starCombinations.length) + "<br>" + logTime(start) + "<br><br>";
	c.innerHTML = myTable + "</table>";

	}

	function logTime(start) {
	var end = performance.now();
	var time = end - start;
	return 'Execution time: ' + time + ' ms';
	}

	function combinations(set, k) {
	var i, j, combs, head, tailcombs;

	if (!set \|\| !k \|\| k > set.length \|\| k <= 0) {
	return [];
	}

	if (k == set.length) {
	return [set];
	}

	if (k == 1) {
	combs = [];
	for (i = 0; i < set.length; i++) {
	combs.push([set[i]]);
	}
	return combs;
	}
	combs = [];
	for (i = 0; i < set.length - k + 1; i++) {
	head = set.slice(i, i + 1);
	tailcombs = combinations(set.slice(i + 1), k - 1);
	for (j = 0; j < tailcombs.length; j++) {
	combs.push(head.concat(tailcombs[j]));
	}
	}
	return combs;
	}
	</script>
	</body>
	</html>