为什么时间限制超过问题在一个代码中显示，而在另一个代码中传递测试用例？

Question

I was solving the next palindrome problem but failed to understand why my code 1 is showing time limit exceeded and not running properly while code2 has passed all test cases? I have used the same concept while doing both the codes but just used procedure in the second case.

Here are the two codes :

code 1

        int no=sc.nextInt();
        boolean check=true;
        int rem,temp,rev=0;
        while(check)
        {
            no++;
            temp=no;
            while(temp>0)
            {
                 rem=temp%10;
                 temp=temp/10;
                 rev=rev*10+rem;

            }
            if(rev==no)
            {
                check=false;
                System.out.println(no);
                break;
            }
        
        }

            
        }
        catch(Exception e)
        {
            System.out.println(e);
        }```



code 2
```    public static void main(String[] args) {
        // TODO code application logic here
        Scanner sc=new Scanner(System.in);
        //Scanner sc=new Scanner(System.in);
        int no=sc.nextInt();
        boolean check=true;
        int rem,temp,temp2=1,rev=0;
        System.out.println(no);
        while(temp2!=0)
        {
            //no=no+1;
            if(pallin(no))
            {
                System.out.println(no);
                temp2=0;
            }
            no++;
        
        }
        
            
        /*while(no<900)
        {   no++;
            //StringBuilder str_no=new StringBuilder(no);
            System.out.println(str_no.reverse());
            
            if(str_no.equals(str_no.reverse()) )
            {
                check=false;
                break;
            } 
        }
        if(check==false)
        {
            System.out.println(no);
        }*/
    }
    private static boolean pallin(int no)
    {
         int rem,temp=no,rev=0;
         while(temp>0)
            {
                 rem=temp%10;
                 temp=temp/10;
                 rev=rev*10+rem;

            }
            System.out.println(rev);
            
            if(rev==no)
            {
                
                System.out.println(rev);
                return true;
              
            }
            return false;
    }
    
}```

Answer 1

I think what is wrong is that you set your int rev=0. When calculating rev=rev*10+rem; you're getting a wrong answer. Moreover, in the nested while loop with condition no>0; no is not changing value.