shiawuen/index.html

## index.html
<!DOCTYPE HTML>
<html lang="en-US">
<head>
  <meta charset="UTF-8">
  <title>Combination – stupid way</title>
</head>
<body>

  <script src="index.js"></script>
</body>
</html>

## index.js
/*
  Given a number n, generate all possible sequences of numbers that add up to n, where the numbers in the
  sequence are in non-ascending order.
  e.g., n=4, then
    4
    3,1
    2,2
    2,1,1
    1,1,1,1
*/
(function(slice, MAX, undef) {

/**
 * Change this value to get different sets
 * of number combinations
 */

var n = 15;


/**
 * Value to get benchmark and calculate total
 * sets generated
 */

var count = 0;
var start, now;

start = +new Date()
compute(n);
now = +new Date()


// end
console.log('Total time spent: ' +(now-start)+ 'ms');
console.log(count + ' combinations generated');


function compute(n1 /*, n2, n3 */) {
  var set = slice.call(arguments)
    , idx = set.length-1
    , last = set[idx]
    , base = set[idx-1]
    , i = last
    , newSet;

  if (base === undef)
    base = MAX;

  if (last <= base) {
    count += 1;
    console.log(set+'');
  }

  while(--i) {

    // Get a copy of the existing set
    newSet = slice.call(set);

    // Skip those that have new value that
    // is larger than the base
    if (i > base) continue;

    newSet[idx] = i;
    newSet.push(last-i);

    compute.apply(null, newSet);
  }
}

})(Array.prototype.slice, Infinity);
	<!DOCTYPE HTML>
	<html lang="en-US">
	<head>
	<meta charset="UTF-8">
	<title>Combination – stupid way</title>
	</head>
	<body>

	<script src="index.js"></script>
	</body>
	</html>
	/*
	Given a number n, generate all possible sequences of numbers that add up to n, where the numbers in the
	sequence are in non-ascending order.
	e.g., n=4, then
	4
	3,1
	2,2
	2,1,1
	1,1,1,1
	*/
	(function(slice, MAX, undef) {

	/**
	* Change this value to get different sets
	* of number combinations
	*/

	var n = 15;


	/**
	* Value to get benchmark and calculate total
	* sets generated
	*/

	var count = 0;
	var start, now;

	start = +new Date()
	compute(n);
	now = +new Date()


	// end
	console.log('Total time spent: ' +(now-start)+ 'ms');
	console.log(count + ' combinations generated');


	function compute(n1 /, n2, n3 /) {
	var set = slice.call(arguments)
	, idx = set.length-1
	, last = set[idx]
	, base = set[idx-1]
	, i = last
	, newSet;

	if (base === undef)
	base = MAX;

	if (last <= base) {
	count += 1;
	console.log(set+'');
	}

	while(--i) {

	// Get a copy of the existing set
	newSet = slice.call(set);

	// Skip those that have new value that
	// is larger than the base
	if (i > base) continue;

	newSet[idx] = i;
	newSet.push(last-i);

	compute.apply(null, newSet);
	}
	}

	})(Array.prototype.slice, Infinity);