#include <bits/stdc++.h>
#define int long long
using namespace std;
string yn(bool ans,string y="YES",string n="NO"){
return (ans?y:n);
}
#define all(a) a.begin(),a.end()
void gogo(){
int n,m;
cin>>n>>m;
vector<vector<int>>a(n,vector<int>(m));
for(int i=0;i<n;i++){
for(int j=0;j<m;j++){
cin>>a[i][j];
}
}
int ans=-INT_MAX;
int mn[n+1][n+1];
for(int i=0;i<n;i++){
for(int j=0;j<m;j++){
mn[i][j]=a[i][j]-i-j;
if(i>0){
mn[i][j]=min(mn[i][j],mn[i-1][j]);
}
if(j>0){
mn[i][j]=min(mn[i][j],mn[i][j-1]);
}
if(j>0 and i){
mn[i][j]=min(mn[i][j],mn[i-1][j-1]);
}
}
}
for(int i=0;i<n;i++){
for(int j=0;j<m;j++){
a[i][j]-=i+j;
ans=max(ans,a[i][j]-mn[i][j]);
}
}
for(int i=0;i<n;i++){
reverse(a[i].begin(),a[i].end());
}
for(int i=0;i<n-i-1;i++){
swap(a[i],a[n-i-1]);
}
int mn[n+1][n+1];
for(int i=0;i<n;i++){
for(int j=0;j<m;j++){
mn[i][j]=a[i][j]-i-j;
if(i>0){
mn[i][j]=min(mn[i][j],mn[i-1][j]);
}
if(j>0){
mn[i][j]=min(mn[i][j],mn[i][j-1]);
}
if(j>0 and i){
mn[i][j]=min(mn[i][j],mn[i-1][j-1]);
}
}
}
for(int i=0;i<n;i++){
for(int j=0;j<m;j++){
a[i][j]-=i+j;
ans=max(ans,a[i][j]-mn[i][j]);
}
}
cout<<ans-1<<endl;
}
main(){
ios_base::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
long long t=1;
// cin>>t;
while(t--){
gogo();
}
}
Compilation message
maxcomp.cpp: In function 'void gogo()':
maxcomp.cpp:45:9: error: redeclaration of 'long long int mn [(n + 1)][(n + 1)]'
45 | int mn[n+1][n+1];
| ^~
maxcomp.cpp:18:9: note: 'long long int mn [(n + 1)][(n + 1)]' previously declared here
18 | int mn[n+1][n+1];
| ^~
maxcomp.cpp: At global scope:
maxcomp.cpp:68:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
68 | main(){
| ^~~~
