JS笛卡尔积算法 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>