搜索和添加元素到一个ArrayList的Array中

Question

public double[] randomSolutions(int[] path) {
    double[] doubleSol = new double[vertices];
    Random r = new Random();
    for (int i = 0; i < doubleSol.length; i++) {
        doubleSol[i] = r.nextDouble();
    }
    return doubleSol;
}

public ArrayList randomDecSol(int[] path) {
    ArrayList<double[]> list = new ArrayList<>();
    int count = 0;
    for (int i = 0; i < 10000; i++) {
        list.add(randomSolutions(path));
    }
    return list;
}

public ArrayList<int[]> doubleToIntArrayList(ArrayList<double[]> list) {
    ArrayList<int[]> RandVerArray = new ArrayList<>();
    int[] randV = new int[vertices];
    for (int i = 0; i < list.size(); i++) {
        for (int j = 0; j < list.get(i).length; j++) {
            double vertex = ((list.get(i)[j] * 100));
            System.out.print(vertex + " ");
            randV[j] = (int) Math.round(vertex);
            System.out.print(randV[j] + " ");
        }
        RandVerArray.add(randV);
        System.out.print(" \n");
    }
    return RandVerArray;
}

public void print(ArrayList<int[]> RandVerArray){
    for(int[] sol : RandVerArray){
        System.out.print(Arrays.toString(sol)+"\n");
    }        
}

我有这4个函数，第一个函数返回一个充满随机双数的数组，然后我创建了一个ArrayList并运行该函数10000次，并将数组添加到ArrayList中。然后我创建了一个ArrayList，并运行该函数10000次，并将数组添加到ArrayList中。然后我在ArrayList中循环，并将数组中每个索引中的双数乘以100，将数字四舍五入，并将其转换为整数，并重复拥有一个数组列表的过程，但用整数代替。然后我试着打印所有的数字，它只重复打印相同的数字，而这恰好是双数组ArrayList中的最后一个数组。这到底是怎么回事？我想不通。

Answer 1

你实际上是在替换数组中的值。randV 修改代码如下

public ArrayList<int[]> doubleToIntArrayList(ArrayList<double[]> list) {
ArrayList<int[]> RandVerArray = new ArrayList<>();
int[] randV = null;
for (int i = 0; i < list.size(); i++) {
    randV = new Integer[vertices];
    for (int j = 0; j < list.get(i).length; j++) {
        double vertex = ((list.get(i)[j] * 100));
        System.out.print(vertex + " ");
        randV[j] = (int) Math.round(vertex);
        System.out.print(randV[j] + " ");
    }
    RandVerArray.add(randV);
    System.out.print(" \n");
}
return RandVerArray;}