Shuffle (shuffle)

Shuffling (Shuffling)

Suppose you have a row order of playing cards, you have to do is reorder making the original order into a disordered arrangement.

• The initial order of the cards is as follows

Sort shuffle (Shuffle sort)

step

• Generating a random number for each of the playing cards
• Playing cards sorted according to the random number under each playing card

Examples

• The initial cards

• Add poker random numbers

• The random numbers are sorted in the poker

Code by java

static public void shuffle(int a[]){
        TreeMap<Float,Integer> tm=new TreeMap<>();//使用Float(随机数)--Integer(数字)键值对的map来存储随机数和数字的组合
                             //同时利用Treemap对键的排序功能对随机数进行排序
        Random r=new Random();//创建Random对象
        for(int i=0;i<a.length;i++)//按顺序给每个数字一个随机数,并添加到Treemap
            tm.put(r.nextFloat(),a[i]);
        int i=0;
        for(Float key:tm.keySet()) {//从Treemap中按顺序取出值,并放入到原数组中
            a[i] = tm.get(key);
            i++;
        }
    }

Feature

• Sorting depending randomness of the randomness of the random number generator
• When faced with a large-scale reshuffle, is actually relatively time-consuming sorting

Knuth shuffle

step

• Each iteration i, randomly selected from a 0-i playing cards in a card with the i-card exchange

Examples

• i iteration i
• R randomly generated number between 0-i of the

Code by java

static public void kunthShuffle(int[] a){
        Random r=new Random();//创建Random对象
        int temp;//交换临时变量
        for(int i=1;i<a.length;i++){//显而易见下标为0的数字不用交换
            int ri=r.nextInt(i+1);//随机生成的0-i的下标
            temp=a[ri];//交换下标为i和下标为ri的两个数
            a[ri]=a[i];
            a[i]=temp;
        }
    }

Feature

• Effective sequence randomizes
• Can be completed within the time-line of