创建唯一的随机数 [英] Creating unique random numbers

问题描述

我创建了以下方法以创建唯一的随机数。 （此唯一值属于树的节点）：

I have created the following method so as to create unique random numbers . (This unique values belong to the nodes of a tree):

  static Random rand = new Random();
public static ArrayList<Node> go(int n) {
    ArrayList<Node> list = new ArrayList<Node>();
    ArrayList<Integer> numList = new ArrayList<Integer>();
    // TODO Auto-generated method stub
    for(int i = 1; i<=5; i++)
    {
        int number = rand.nextInt(10)+1;
        if(list.size()>0 && !check(list,number))
        {
            i--;
            continue;
        }
        numList.add(number);
        Node node = new Node();
        node.data = number;
        list.add(node);
    }
     int w  = 0;
    for (Node d : list) {
        System.out.println(w+": "+d.data);
        w++;
    }
    return list;

}
  private static boolean check(ArrayList<Node> list, int num) {
    // TODO Auto-generated method stub
    boolean b = false;
    /*if(list.size()==0)
        return true;
    */
    for (Node node : list) {
        if(node.data == num)
            b = false;
        else
            b = true;
    }
    return b;
}

但它不会创建唯一的数字，我的列表中仍然有重复数字。喜欢：

But it doesn’t create unique numbers and there are still duplicates in my list. Like :

0: 10
1: 1 
2: 10 
3: 5 
4: 6 

推荐答案

问题在于如果找到重复的数字，你不会在check函数内停止for循环。循环继续，b可以变回true。

The problem is that you don't stop the for loop inside the check function if it finds a duplicated number. The loop continues and b can change back to true.

你应该做的是例如：

  private static boolean check(ArrayList<Node> list, int num) {
    for (Node node : list) {
        if(node.data == num)
            return false;
    }
    return true;
}

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