JS笛卡尔积算法与多重数组笛卡尔积实现方法示例

//笛卡儿积组合
function descartes(list) {
 //parent上一级索引;count指针计数
 var point = {};
 var result = [];
 var pIndex = null;
 var tempCount = 0;
 var temp = [];
 //根据参数列生成指针对象
 for (var index in list) {
 if (typeof list[index] == 'object') {
 point[index] = {
 'parent': pIndex,
 'count': 0
 }
 pIndex = index;
 }
 }
 //单维度数据结构直接返回
 if (pIndex == null) {
 return list;
 }
 //动态生成笛卡尔积
 while (true) {
 for (var index in list) {
 tempCount = point[index]['count'];
 temp.push(list[index][tempCount]);
 }
 //压入结果数组
 result.push(temp);
 temp = [];
 //检查指针最大值问题
 while (true) {
 if (point[index]['count'] + 1 >= list[index].length) {
 point[index]['count'] = 0;
 pIndex = point[index]['parent'];
 if (pIndex == null) {
 return result;
 }
 //赋值parent进行再次检查
 index = pIndex;
 } else {
 point[index]['count']++;
 break;
 }
 }
 }
}

var result = descartes({'aa':['a','b','c','d'],'bb':['$','%','^','&']});
alert(result);//result就是笛卡尔积

<script>
(function() {
 dwn = function(a) {
 document.writeln(a + "<br />")
 };
 //笛卡尔积
 var Cartesian = function(a, b) {
 var ret = [];
 for (var i = 0; i < a.length; i++) {
 for (var j = 0; j < b.length; j++) {
 ret.push(ft(a[i], b[j]));
 }
 }
 return ret;
 }
 var ft = function(a, b) {
 if (! (a instanceof Array)) a = [a];
 var ret = Array.call(null, a);
 ret.push(b);
 return ret;
 }
 //多个一起做笛卡尔积
 multiCartesian = function(data) {
 var len = data.length;
 if (len == 0) return [];
 else if (len == 1) return data[0];
 else {
 var r = data[0];
 for (var i = 1; i < len; i++) {
 r = Cartesian(r, data[i]);
 }
 return r;
 }
 }
})();
var data = [['a', 'b', 'c'], [1, 2, 3, 4], ['A', 'B'], ['#', '@', '+'], ['Mary', 'Terry', 'KYO']];
var r = multiCartesian(data);
for (var i = 0; i < r.length; i++) {
 dwn("(" + r[i] + ")");
}
</script>