迪卡尔积

 
非递归版本
private static List<List<Double>> circulate (List<List<Double>> dimValue) {  
	        int total = 1;  
	        for (List<Double> list : dimValue) {  
	            total *= list.size();  
	        }  
	        List<List<Double>> myResult = new ArrayList<List<Double>>();
	        int itemLoopNum = 1;  
	        int loopPerItem = 1;  
	        int now = 1;  
	        for (List<Double> list : dimValue) {  
	            now *= list.size();  
	  
	            int index = 0;  
	            int currentSize = list.size();  
	  
	            itemLoopNum = total / now;  
	            loopPerItem = total / (itemLoopNum * currentSize);  
	            int myIndex = 0;  
	            for (Double string : list) {  
	                for (int i = 0; i < loopPerItem; i++) {
	                    if (myIndex == list.size()) {  
	                        myIndex = 0;  
	                    }  
	                    for (int j = 0; j < itemLoopNum; j++) {
	                    	if(index>myResult.size()-1){
	                    		List<Double> tmp = new ArrayList<Double>();
	                    		tmp.add(list.get(myIndex));
	                    		myResult.add(tmp);
	                    	}else{
	                    		myResult.get(index).add(list.get(myIndex));
	                    	}
	                        index++;  
	                    }  
	                    myIndex++;  
	                }  
	            }  
	        }  
	        return myResult;
	    }

递归版本
private static void recursive (List<List<Double>> dimValue, List<List<Double>> result, int layer, List<Double> curList) {  
        if (layer < dimValue.size() - 1) {  
            if (dimValue.get(layer).size() == 0) {  
                recursive(dimValue, result, layer + 1, curList);  
            } else {  
                for (int i = 0; i < dimValue.get(layer).size(); i++) {  
                    List<Double> list = new ArrayList<Double>(curList);  
                    list.add(dimValue.get(layer).get(i));  
                    recursive(dimValue, result, layer + 1, list);  
                }  
            }  
        } else if (layer == dimValue.size() - 1) {  
            if (dimValue.get(layer).size() == 0) {  
                result.add(curList);  
            } else {  
                for (int i = 0; i < dimValue.get(layer).size(); i++) {  
                    List<Double> list = new ArrayList<Double>(curList);  
                    list.add(dimValue.get(layer).get(i));  
                    result.add(list);  
                }  
            }  
        }  
    }