#include <iostream>
#include <bits/stdc++.h>
#include <cmath>
#include <algorithm>
#include <vector>
#include <deque>
#include <set>
#include <stack>
#include <string>
#include <map>
#include <queue>
#define int long long
using namespace std;
const long long oo = 1000000000000000000;
long long sum, ans = 0, mx = 0, mn = 1000000000, num, pos;
/*
ViHHiPuh
(( `'-""``""-'` ))
)-__-_.._-__-(
/ --- (o _ o) --- \
\ .-* ( .0. ) *-. /
_'-. ,_ '=' _, .-'_
/ `;#'#'# - #'#'#;` \
\_)) -----'#'----- ((_/
# --------- #
'# ------- ------ #'
/..-'# ------- #'-.\
_\...-\'# -- #'/-.../_
((____)- '#' -(____))
cout << fixed << setprecision(6) << x;
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
freopen ( "sum.in", "r", stdin )
*/
set<int> dp[ 1001 ][ 1001 ][ 2 ];
int a[ 1001 ][ 1001 ];
main () {
int n, m;
cin >> n >> m;
for ( int i = 0; i < n; i ++ ) {
for ( int j = 0; j < m; j ++ ) {
cin >> a[ i ][ j ];
}
}
if ( n * m <= 20 ) {
for ( int mask = 0; mask < ( 1 << ( n * m ) ); mask ++ ) {
for ( int i = 0; i < n; i ++ ) {
for ( int j = 0; j < m; j ++ ) {
num = ( i ) * m + j;
if ( mask & ( 1 << num ) ) {
ans = 0;
if ( i ) {
if ( mask & ( 1 << ( num - m ) ) )
ans = 1;
}
if ( j )
if ( mask & ( 1 << ( num - 1 ) ) )
ans = 1;
if ( i < n - 1 )
if ( mask & ( 1 << ( num + m ) ) )
ans = 1;
if ( j < m - 1 ) {
if ( mask & ( 1 << ( num + 1 ) ) )
ans = 1;
}
}
if ( !ans )
break;
}
if ( !ans )
break;
}
if ( !ans )
continue;
st.clear();
for ( int i = 0; i < n; i ++ ) {
for ( int j = 0; j < m; j ++ ) {
num = i * m + j;
if ( mask & ( 1 << num ) ) {
mx = max( mx, a[ i ][ j ] );
mn = min( mn, a[ i ][ j ] )
sum ++;
}
}
}
ans = max( ans, mx - mn - sum );
mx = 0;
sum = 0;
mn = oo;
}
cout << ans;
}
else {
}
}
/*
4
3 3 4
4 ^ 6 ^ 8 ^ 5 ^ 6 ^ 7 = 14
2 3
2 4 3
5 7 5
*/
Compilation message
maxcomp.cpp:50:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
50 | main () {
| ^~~~
maxcomp.cpp: In function 'int main()':
maxcomp.cpp:88:4: error: 'st' was not declared in this scope; did you mean 'std'?
88 | st.clear();
| ^~
| std
maxcomp.cpp:94:34: error: expected ';' before 'sum'
94 | mn = min( mn, a[ i ][ j ] )
| ^
| ;
95 | sum ++;
| ~~~
