Language: C++

import java.util.*;
class C {
	public static void main(String arg[]){
		while(true){
			Scanner cs=new Scanner(System.in);
			int ans=0;
			int n=cs.nextInt();
			int m=cs.nextInt();
			if (n==0)break;
			int a[][]=new int[n+1][m+1];
			int s[][]=new int[n+1][m+1];
			for (int i=1;i<=n;i++)
				for(int j=1;j<=m;j++){
					a[i][j]=cs.nextInt();
				}
			for (int i=0;i<n;i++)
				for (int j=0;j<m;j++){
					s[i][j]=0;
				}
			for (int i=1;i<n;i++)
				for (int j=1;j<m;j++){
					s[i][j]=s[i][j-1]+s[i-1][j]-s[i-1][j-1]+a[i][j];
				}
			for (int st1=1;st1<n;st1++)
				for (int st2=1;st2<m;st2++)
					for (int en1=st1+2;en1<=n;en1++)
						for (int en2=st2+2;en2<=m;en2++){
							int min=a[st1][st2];
							for(int i=st1;i<=en1;i++){
								if (min>a[i][st2])min=a[i][st2];
								if (min>a[i][en2])min=a[i][en2];
							}
							for(int i=st2;i<=en2;i++){
								if (min>a[st1][i])min=a[st1][i];
								if (min>a[en1][i])min=a[en1][i];
							}
							int max=a[st1+1][st2+1];				
							for (int i=st1+1;i<en1;i++)
								for (int j=st2+1;j<en2;j++)
									if (max<a[i][j])max=a[i][j];
							if (max<min&& ans<min*(en1-st1-1)*(en2-st2-1)-(s[en1-1][en2-1]-s[st1][en2-1]-s[en1-1][st2]+s[st1][st2]))
								ans=min*(en1-st1-1)*(en2-st2-1)-(s[en1-1][en2-1]-s[st1][en2-1]-s[en1-1][st2]+s[st1][st2]);
						}
			System.out.println(ans);
		}
	}
}


Compiler output:
a.cc:1:1: error: 'import' does not name a type
    1 | import java.util.*;
      | ^~~~~~
a.cc:1:1: note: C++20 'import' only available with '-fmodules-ts'
a.cc:3:15: error: expected ':' before 'static'
    3 |         public static void main(String arg[]){
      |               ^~~~~~~
      |               :
a.cc:3:33: error: 'String' has not been declared
    3 |         public static void main(String arg[]){
      |                                 ^~~~~~
a.cc:47:2: error: expected ';' after class definition
   47 | }
      |  ^
      |  ;
a.cc: In static member function 'static void C::main(int*)':
a.cc:5:25: error: 'Scanner' was not declared in this scope
    5 |                         Scanner cs=new Scanner(System.in);
      |                         ^~~~~~~
a.cc:7:31: error: 'cs' was not declared in this scope
    7 |                         int n=cs.nextInt();
      |                               ^~
a.cc:10:29: error: declaration of 'a' as multidimensional array must have bounds for all dimensions except the first
   10 |                         int a[][]=new int[n+1][m+1];
      |                             ^
a.cc:10:51: error: array size in new-expression must be constant
   10 |                         int a[][]=new int[n+1][m+1];
      |                                                   ^
a.cc:10:49: error: the value of 'm' is not usable in a constant expression
   10 |                         int a[][]=new int[n+1][m+1];
      |                                                ~^~
a.cc:11:29: error: declaration of 's' as multidimensional array must have bounds for all dimensions except the first
   11 |                         int s[][]=new int[n+1][m+1];
      |                             ^
a.cc:11:51: error: array size in new-expression must be constant
   11 |                         int s[][]=new int[n+1][m+1];
      |                                                   ^
a.cc:11:49: error: the value of 'm' is not usable in a constant expression
   11 |                         int s[][]=new int[n+1][m+1];
      |                                                ~^~
a.cc:14:41: error: 'a' was not declared in this scope
   14 |                                         a[i][j]=cs.nextInt();
      |                                         ^
a.cc:18:41: error: 's' was not declared in this scope
   18 |                                         s[i][j]=0;
      |                                         ^
a.cc:22:41: error: 's' was not declared in this scope
   22 |                                         s[i][j]=s[i][j-1]+s[i-1][j]-s[i-1][j-1]+a[i][j];
      |                                         ^
a.cc:22:81: error: 'a' was not declared in this scope
   22 |                                         s[i][j]=s[i][j-1]+s[i-1][j]-s[i-1][j-1]+a[i][j];
      |                                                                                 ^
a.cc:28:65: error: 'a' was not declared in this scope
   28 |                                                         int min=a[st1][st2];
      |                                                                 ^
a.cc:41:104: error: 's' was not declared in this scope
   41 |                                                         if (max<min&& ans<min*(en1-st1-1)*(en2-st2-1)-(s[en1-1][en2-1]-s[st1][en2-1]-s[en1-1][st2]+s[st1][st2]))
      |                                                                                                        ^
a.cc:44:25: error: 'System' was not declared in this scope
   44 |                         System.out.println(ans);
      |                         ^~~~~~