Question

这样做的目的是在给定10 x 10矩阵内的一组坐标时打印出斑点的大小。它是用Java编写的，练习的重点是使用递归在blob中找到每个1。（通过向上，向下，向左或向右连接到原始坐标的任何1。

Example:
The Blob
    0010010010
    0100100101
    1001001010
    0011110101
    0111101010
    1001010100
    0010101101
    0101010010
    1010100100
    0101001000
The Coordinates
    1 1
    2 3
    5 7
The Output
1
10
3



      import java.util.*;
        
        public class BlobsRunner
        {   
            public static void main(String[] args)
            {
                //test the Blob class to make sure
            //it works as intended
            Blobs bloop = new Blobs(10, 10);
            //call both constructors
            Scanner reader = new Scanner(System.in);
            System.out.println("Row: ");
            int r = reader.nextInt();
            System.out.println("Colum: ");
            int c = reader.nextInt();
            bloop.recur(r, c);
            bloop.getBlobCount();
            //print the newly instantiated Blob
            bloop.toString();
            //call methods - print out the size of the blob
            //bloop.getBlobCount();  
        }   
    }

//next file

import java.util.*;

public class Blobs
{
    private int[][] mat;   //grid of 1s and 0s
    private int count;
    private int[][] visited;
    public Blobs( int rows, int cols )
    {
        //set count to 0
        count = 0; 
        //point mat at new mat size rows X cols 
        mat = new int[rows][cols];          
        //loop through mat
        for(int a = 0; a < rows; a ++)
        {
            for(int b = 0; b< cols; b++)
            {
                mat[a][b] = (int)Math.random();
            }
        }
           //fill in mat with 1s and 0s 
           //use Math.random()
        visited = new int[rows][cols];
    }

    public Blobs( int rows, int cols, String s )//what does s mean?
    {
        //set count to 0
        count = 0;
        //point mat at new mat size rows X cols 
        mat = new int[rows][cols];  
        for(int a = 0; a < rows; a ++)
        {
            for(int b = 0; b< cols; b++)
            {
                mat[a][b] = (int)Math.random();
            }
        }
        visited = new int[rows][cols];
        //loop through mat
           //load in the 1s and 0s from s
    
    }
    
    public void recur(int r, int c)
    {
        //add a base case
        if(mat[r][c]==0)
        {
            //return;
        }
        if(visited[r][c] == 5)//figure out, make sure it doesn't count if it does
        {
            //return;
        }
        visited[r][c] = 5;
            //mark current pos as visited   
        count++;
            //increase count by 1   
            //add in 4 recursive calls
        //UP
        if(mat[r+1][c] == 1 && visited[r+1][c] != 5)
        {
            recur(r+1, c);
        }
        //DOWN
        if(mat[r-1][c] == 1 && visited[r-1][c] != 5)
        {
            recur(r-1,c);
        }
        //LEFT
        if(mat[r][c-1] == 1 && visited[r][c-1] != 5)
        {
            recur(r,c-1);
        }
        //RIGHT
        if(mat[r][c+1] == 1 && visited[r][c+1] != 5)
        {
            recur(r,c+1);
        }
    }

    public int getBlobCount()
    {
        //return count
        return 0;
    }

    public String toString()
    {
        //you will need nested loops
        //you will need a local string variable
        for(int a = 0; a < mat.length; a++)
        {
            for(int b = 0; b < mat[a].length; b++)
            {
                System.out.print(mat[a][b]);
            }
            System.out.println();
        }
        return "";
    }
}

Answer 1

def add(self, question, answer): temp = trivia(question, answer) if not self.head: # first node self.head = temp temp.setNext(self.head) # single node, loop to itself else: # add node temp.setNext(self.head.getNext()) # shift loop self.head.setNext(temp) # insert just after head函数返回0到1之间的双精度值，因此当您尝试将其转换为Math.random()时，它变为0。因此，所有矩阵均为0。由于在{{ 1}}发挥其打印10x10 0矩阵的作用。

尝试先添加(int)，然后再添加recur()，然后再分配随机数import java.util.Random;

Answer 2

正如 @Fatih Aslan 所指出的，div在0.0和1.0之间产生一个双精度值，不包括1.0。解析为int时，Java始终会产生值0。

如果您不想使用Math.random()库，可以将要从java.util.Random获得的值乘以要生成的最高和最低随机数之间的差加1。如果希望最小的随机数大于0，则将该数字添加到Math.random()的输出中。

例如，Math.random()将产生2到10的随机整数，包括2和10。

代码没有打印任何东西，我找不到问题

2 个答案: