#include<bits/stdc++.h>

using namespace std;
int main()
{
	int i;
	int g;
	int o=0;
	int k = 0;
	cin >> i;
	int a[100][100];//创建二维数组
	for (int f = 0; f <= i - 1; f++)//储存数据(行
	{
		for (int m = 0; m <= i - 1; m++)//储存数据(列
		{
			cin >> g;
			a[f][m] = g;
		}
	}
	for (int f = 0; f <= i - 1; f++)
	{
		o = o + a[f][f];
	}
	for (int f = i - 1; f >= 0; f--)
	{
		k = k + a[f][i-1 - f];
	}
	cout << o << endl;
	cout << k;
}

二维数组 tips:二位数组不要开太大，会爆炸

n = int(input())
l = []
p = n
while n:
    t = list(map(int,input().split()))
    l.append(t)
    n-=1

a,b = 0,0
for i in range(p):
    a+=l[i][i]
    b+=l[p-i-1][i]

print(a)
print(b)

C++ :

#include <iostream>
#include <cstdio>
#define Maxn 1000
using namespace std;
int a[Maxn][Maxn];
int main()
{
    int n;
    long long d=0,b=0;
    scanf("%d",&n);
    for(int i=1;i<=n;i++){
        for(int j=1;j<=n;j++){
            scanf("%d",&a[i][j]);
        }
    }
    for(int c=1;c<=n;c++){
        d=d+a[c][c];
    }
    for(int c=1;c<=n;c++){
       int e=n-c+1;
       b=b+a[c][e];
    }
    printf("%lld %lld\n",d,b);



    return 0;
}

#include<bits/stdc++.h>
using namespace std;
int n,ans1,ans2,a[105][105];
int main(){
    cin>>n;
    for(int i=1;i<=n;i++){
        for(int j=1;j<=n;j++){
            cin>>a[i][j];
        }
    }
    for(int i=1;i<=n;i++){
        ans1+=a[i][i];
        ans2+=a[i][n-i+1];
    }
    cout<<ans1<<endl<<ans2;
    return 0;
}