Random generation of nine palace pattern cipher - Implementation

Keywords: Java

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I didn't mean to see a string of code that I wrote again after I practiced my basic skills at home after I failed an interview.

There are tens of thousands of methods. The following are the most impressive ones for me. Looking back, I still think it's meaningful to learn, so I send them out to share learning.

The original condition of the problem is not remember too Qing, and the general realization is: randomly generate the nine palace pattern (gesture) password

 

There are several points to read:
1. Password length can be set

2. The path of gesture password must be direct

It can be realized in two ways:

1. Can arr judge whether the value before and after can reach directly

2. getNum gets the next value based on the previous value

package com.maomao;

import org.testng.annotations.Test;
import java.util.HashMap;
import java.util.Map;

//Random generated nine grid graphic password, random number range 1~9
public class RandomScret {

    //9 In the grid, 1~9 Direct numerical value, discovery rule
    //Except for 5
    //Odd number, 1, 3, 7, 9, four corners can't be reached directly
    //Even numbers, 2, 4, 6, 8, diagonals are not directly accessible, and the difference between diagonals and 5 is the same
    //    int[] num_1={2,4,5,6,8};
    //    int[] num_2={1,3,4,5,6,7,9};
    //    int[] num_3={2,4,5,6,8};
    //    int[] num_4={1,2,3,5,7,8,9};
    //    int[] num_5={1,2,3,4,6,7,8,9};
    //    int[] num_6={1,2,3,5,7,8,9};
    //    int[] num_7={2,4,5,6,8};
    //    int[] num_8={1,3,4,5,6,7,9};
    //    int[] num_9={2,4,5,6,8};

    //Get 1~9 Random integer of
    //( n~m Random number formula:(int)(Math.random()*(m-n+1) +n)))
    public static int getRandomNum(){
        int num=(int)(Math.random()*9+1);
        return num;
    }

    //Judge whether it can arrive -----It's a way of trial and error,Takes a long time
    public Boolean canArr(int preNum,int randomNum){
        //Mark, not reachable by default
        boolean flag = false;
        //Before and after values cannot be equal
        if (preNum!=randomNum){
            if (preNum==5 ) {
                flag = true;
            }else if (randomNum==5){
                flag = true;
            }else if (preNum%2==0){ //It's even
                int n=Math.abs(preNum-5);
                int m=Math.abs(randomNum-5);
                if (n!=m){
                    flag=true;
                }
            }else if (preNum%2==1){ //preNum It's an odd number except five
                if (randomNum%2==0){
                    flag=true;
                }
            }
        }

        return flag;
    }

    //Construct a direct path ------This method takes up memory and takes a short time
    public Map<Integer,int[]> All() {
        Map<Integer, int[]> map = new HashMap<>();
        map.put(1,new int[]{2,4,5,6,8});
        map.put(2,new int[]{1,3,4,5,6,7,9});
        map.put(3,new int[]{2,4,5,6,8});
        map.put(4,new int[]{1,2,3,5,7,8,9});
        map.put(5,new int[]{1,2,3,4,6,7,8,9});
        map.put(6,new int[]{1,2,3,5,7,8,9});
        map.put(7,new int[]{2,4,5,6,8});
        map.put(8,new int[]{1,3,4,5,6,7,9});
        map.put(9,new int[]{2,4,5,6,8});

        return map;
    }
    public int getNum(int preNum){
//        int tag=(int)(Math.random()*10);
        int[] nextArr=All().get(preNum);
        int tag=(int)(Math.random()*10+1);//1~10
        int next=nextArr[tag%nextArr.length];
        return next;
    }

    @Test
    public void test1(){
        RandomScret rs=new RandomScret();

        //Set password length length
        int length=6;
        int[] scret=new int[length];

        //Specify build
        int preNum=getRandomNum();
        for (int i=0;i<length;i++){
            scret[i]=rs.getNum(preNum);
            preNum=scret[i];
        }

        for (int num:scret){
            System.out.println(num);
        }
    }

    @Test
    public void test2(){
        RandomScret rs=new RandomScret();

        //Set password length length
        int length=6;
        int[] scret=new int[length];

        //Random generation
        int preNum=getRandomNum();
        for (int i=0;i<length;){
            int randomNum=getRandomNum();
            if (rs.canArr(preNum,randomNum)){
                scret[i]=randomNum;
                preNum=scret[i];
                i++;
            }else {
                continue;
            }
        }

        for (int num:scret){
            System.out.println(num);
        }
    }
}

Posted by Shaun13 on Wed, 13 May 2020 08:19:22 -0700