嘿，所以我不明白为什么遍历这个 ArrayList 会给我一个无限循环？

Question

Hey so I have just been using ArrayList for a particular problem but Here it is giving me an infinite loop still. According to logic the control should enter into one of the break statements after a few iterations but I just cannot figure out why I am getting this error. I have sorted the array b and I am comparing the contents of arraylist a with the maximum element of array b. for eg- a= 1,2,3,4 and maximum of element b=3

if the first element is lesser them max(b[]) then after removing that element the new arraylist becomes 2, 3,4 2 becomes the first element and so on and so forth.

package codechef;

/* package codechef; // don't place package name! */

import java.util.*;
import java.lang.*;
import java.io.*;
/*
5 
3 1 
4 3 5 
6 
3 3 
2 4 7 
2 3 7 
3 3 
2 7 4 
2 7 3 
4 4 
2 6 5 1 
4 6 5 2 
2 2 
7 4 
7 4 
 
 */
/* Name of the class has to be "Main" only if the class is public. */
class codechef2
{
        public static void main (String[] args) throws java.lang.Exception
        {
            try
            {
                    Scanner ob=new Scanner (System.in);
                    int t=ob.nextInt();
                    
                    while(t-->0)
                    {
                        int n=ob.nextInt();
                        int m=ob.nextInt();
                        ArrayList <Integer> a=new ArrayList<Integer>();
                        int b[]=new int[m]; 
                        for(int i=0;i<n;i++)
                        {
                            a.add(ob.nextInt());
                        }
                        for(int i=0;i<n;i++)
                        {
                            System.out.println(a.get(i));
                        }
                        
                        for(int i=0;i<m;i++)
                        {
                            b[i]=ob.nextInt();
                        }
                        ob.close();
                        Arrays.sort(b);
                        int j=0;
                        String str="";
                        boolean flag=false;
                        while(true)
                        {
                            
                            if(b[m-1]>a.get(0))
                            {
                                a.remove(0);
                            }
                            if(a.get(0)>=b[m-1])
                            {
                                flag=true;
                                str="NO";
                                break;
                            }
                            if(a.isEmpty())
                            {
                                str="YES";
                                break;
                            }
                            
                        }
                        System.out.println("brej");
                        if(flag)
                        {
                            System.out.println(str);
                            
                        }
                        else
                        {
                            for(int i:b)
                            {
                                System.out.print(i+" ");
                            }
                        }
                    }
                }
            
            catch(Exception t)
            {
                return;
            }
            
            
        }
        
       
    
}

Answer 1

Look here:

   while(true)
                        {
                            
                            if(b[m-1]<a.get(0))
                            {
                                a.remove(0);
                            }
                            if(a.get(0)>=b[m-1])
                            {
                                flag=true;
                                str="NO";
                                break;
                            }
                            if(a.isEmpty())
                            {
                                str="YES";
                                break;
                            }
                            
                        }

See something wrong with the logic?

b[m-1] < a.get(0) is the exact same condition as a.get(0) >= b[m-1] . You need switch the logic to something like b[m-1]>=a.get(0) to avoid an infinite loop, otherwise it won't break. I also suggest trying to use if / else if / else for this kind of stuff.

Answer 2

You can Fix your Programm with.

else { for(int i:b) { System.out.print(i+" "); } break;

                    }

This will finish your doomsday Loop for while(True)