Codeforces Round #593 (Div. 2), problem: (C) Labs

#pragma GCC optimize("Ofast")
#pragma GCC target("avx,avx2,fma")
#pragma GCC optimization ("unroll-loops")

#include<bits/stdc++.h>
using namespace std;
#define pb push_back
#define pii pair<int,int>
#define pli pair<long long int,int>
#define pbi pair<bool,int>
#define pob pop_back
#define all(a) a.begin(),a.end()
#define fio ios_base::sync_with_stdio(false); cin.tie(0);cout.tie(0);
#define i64 long long int
#define mem(x,y) memset(x,y,sizeof(x))
#define fill(arr,b) fill(arr, arr+sizeof(arr)/sizeof(arr[0]), b)
#define maxarr(n,arr,m) m =-1e9;for(int i=0;i<n;i++)if(arr[i]>m) m=arr[i];
#define read freopen("input.txt","r",stdin);

const double pi = acos(-1.0);
const int maxn = (i64)1e9+7;
int arr[305][305];
int main()
{
    //read;
    int n;
    cin >> n;
    int x=n*n;
    for(int i=1,j=1,k=1;i<=x;i++,k++)
    {
        if(j&1) arr[n-k+1][j]=i;
        else arr[k][j]=i;
        if(i%n==0) {j++;k=0;}
    }
    for(int i=1;i<=n;i++)
    {
        for(int j=1;j<=n;j++) cout<<arr[i][j]<<" ";
        cout<<endl;
    }
    return 0;
}