Question

我想从以下提取所有可能的组合包含所有数据的数组列表具有此结构

ArrayList<object> students = new ArrayList<object>();
ArrayList<object> staff = new ArrayList<object>();
ArrayList<object> uni = new ArrayList<object>();
ArrayList<object> exam = new ArrayList<object>();

ArrayList<ArrayList<object>> main = new ArrayList<object>();
main.add(this.students);
main.add(this.staff);
main.add(this.uni);
main.add(this.exam);

类对象只有两个变量

class object {
    public String name; 
    public double cost;
}

此主变量包含表中所示的以下数据，每列可能具有1到100的值，但这并不意味着每列必须具有相同数量的值

|学生|员工| UNI --- |考试|
| 500 -------- | 400-- | 1400 | 20000 |
| 350 -------- | 250-- | 1100 | 10000 |

所以我想提取的是类似的东西 500 =＆GT; 400 = GT; 1400 =＆GT; 20000个
500 =＆GT; 400 = GT; 1400 =＆GT; 10000

500 =＆GT; 400 = GT; 1100 =＆GT; 20000个
500 =＆GT; 400 = GT; 1100 =＆GT; 10000

500 =＆GT; 250 =＆GT; 1400 =＆GT; 20000个
500 =＆GT; 250 =＆GT; 1400 =＆GT; 10000

500 =＆GT; 250 =＆GT; 1100 =＆GT; 20000个
500 =＆GT; 250 =＆GT; 1100 =＆GT; 10000

350 =＆GT; 400 = GT; 1400 =＆GT; 20000个
350 =＆GT; 400 = GT; 1400 =＆GT; 10000

350 =＆GT; 400 = GT; 1100 =＆GT; 20000个
350 =＆GT; 400 = GT; 1100 =＆GT; 10000

350 =＆GT; 250 =＆GT; 1400 =＆GT; 20000个
350 =＆GT; 250 =＆GT; 1400 =＆GT; 10000

350 =＆GT; 250 =＆GT; 1100 =＆GT; 20000个
350 =＆GT; 250 =＆GT; 1100 =＆GT; 10000

我该怎么做？

Answer 1

这样一个简单的递归函数怎么样？

ArrayList<ArrayList<object>> combs = new ArrayList<>();
object[] comb = new object[main.size()];

void generate(int pos) {
    if (pos == comb.length)
        combs.add(new ArrayList<object>(Arrays.asList(comb)));
    else {
        ArrayList<object> arr = main.get(pos);
        for (object el : arr) {
            comb[pos] = el;
            generate(pos + 1);
        }
    }
}

从对象的arraylist的arraylist获得所有可能的组合

1 个答案: