60分求调

#include <bits/stdc++.h>
#define ll long long
using namespace std;
ll n,m,a[90][90],f[90][90],ans;
void out(ll x){
    if(x>9)cout<<x/10;
    putchar(x%10+'0');
}signed main () {
	cin>>n>>m;
	for(ll i=1;i<=n;++i)for(ll j=1;j<=m;++j)cin>>a[i][j];
	for(ll i=1;i<=n;ans+=f[1][m],memset(f,0,sizeof(f)),++i)for(ll len=1;len<=m;++len)for(ll l=1,r=l+len-1;r<=m;++l,++r)f[l][r]=max(f[l+1][r]+a[i][l],f[l][r-1]+a[i][r])*2;
	cout<<ans;
	return 0;
}