OGCA

→ → → ↓
↓ ← ← ←
→ → → ↓
↓ ← ← ←

#include <iostream>
using namespace std;

int main(){
    int n,a[100][100],cnt = 1;
    cin >> n;
    for(int i = 0;i < n;i++){
        if(i%2==0){//--->
            for(int j = 0;j < n;j++){
                a[i][j] = cnt;
                cnt++;
            }
        }else{
            for(int j = n-1;j >= 0;j--){
                a[i][j] = cnt;
                cnt++;
            }
        }
    }
    for(int i = 0;i < n;i++){
        for(int j = 0;j < n;j++){
            cout << a[i][j] << ' ';
        }
        cout << endl;
    }
    return 0;
}