95pts求助

#include<bits/stdc++.h>
using namespace std;
int Read();
int n;
int a[1007][1007],b[1007][1007];
int maxn[1007],tot,ans,thistime,maxn2;
int main(){
	n=Read();
	for(int i=1;i<=n;++i)
		for(int j=1;j<=n;++j)
			a[i][j]=Read();
		
			
	for(int t=2;t<n;++t){
		thistime=0;
		for(int i=t;i<=n;++i)thistime+=a[i][i-t+1];
		for(int i=t-1;i>=1;--i)thistime+=a[i][-i+t+1];
		for(int i=2;i<=n-t+1;++i)thistime+=a[i][i+t-1];
		for(int i=n-t+2;i<n;++i)thistime+=a[i][-i+2*n-t+1];
		if(thistime==maxn[0]){
			maxn[++tot]=t;
		}
		if(thistime>maxn[0]){
			memset(maxn,0,sizeof(maxn));
			maxn[0]=thistime;
			tot=0;
			maxn[++tot]=t;
		}
	}
	thistime=0;
	for(int i=1;i<=n;++i)thistime+=a[i][i];
	if(thistime>maxn[0]){
		memset(maxn,0,sizeof(maxn));
		maxn[0]=thistime;
		tot=0;
		maxn[++tot]=1;
		}
	if(thistime==maxn[0]){
		maxn[++tot]=1;
	}
	thistime=0;
	for(int i=1;i<=n;++i)thistime+=a[i][n-i+1];
	if(thistime>maxn[0]){
		memset(maxn,0,sizeof(maxn));
		maxn[0]=thistime;
		tot=0;
		maxn[++tot]=n;
		}
	if(thistime==maxn[0]){
		maxn[++tot]=n;
	}
	
	
	for(int iii=1;iii<=tot;++iii){
		for(int i=1;i<=n;++i)
			for(int j=1;j<=n;++j)
				b[i][j]=a[i][j];
		
		int maxi1=maxn[iii];
		if(maxi1!=1&&maxi1!=n)
		for(int t=maxi1;t==maxi1;++t){
			for(int i=t;i<=n;++i)b[i][i-t+1]=0;
			for(int i=t-1;i>=1;--i)b[i][-i+t+1]=0;
			for(int i=2;i<=n-t+1;++i)b[i][i+t-1]=0;
			for(int i=n-t+2;i<n;++i)b[i][-i+2*n-t+1]=0;
		}
		if(maxi1==1)
		for(int i=1;i<=n;++i)b[i][i]=0;
		if(maxi1==n)
		for(int i=1;i<=n;++i)b[i][-i+n+1]=0;
		
		for(int t=2;t<n;++t){
			thistime=0;
			for(int i=t;i<=n;++i)thistime+=b[i][i-t+1];
			for(int i=t-1;i>=1;--i)thistime+=b[i][-i+t+1];
			for(int i=2;i<=n-t+1;++i)thistime+=b[i][i+t-1];
			for(int i=n-t+2;i<n;++i)thistime+=b[i][-i+2*n-t+1];
			if(thistime>maxn2){maxn2=thistime;}
		}
		thistime=0;
		for(int i=1;i<=n;++i)thistime+=b[i][i];
		if(thistime>maxn2){maxn2=thistime;}
		thistime=0;
		for(int i=1;i<=n;++i)thistime+=b[i][n-i+1];
		if(thistime>maxn2){maxn2=thistime;}
	}
//	cout<<maxn[0]<<" "<<maxn2<<"\n";
	cout<<maxn[0]+maxn2<<"\n";
	return 0;
}
int Read(){
	char ch=getchar();
	int res=0,flag=1;
	while(ch<'0'||ch>'9'){
		if(ch=='-')flag=-1;
		ch=getchar();
	}
	while(ch>='0'&&ch<='9'){
		res=(res<<3)+(res<<1)+ch-'0';
		ch=getchar();
	}
	return flag*res;
}