Language: C++

#include <bits/stdc++.h>
using namespace std;
//#pragma GCC optimize("Ofast")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")

#define ms(s, n) memset(s, n, sizeof(s))
#define FOR(i, a, b) for (int i = (a); i < (b); ++i)
#define FORd(i, a, b) for (int i = (a) - 1; i >= (b); --i)
#define FORall(it, a) for (__typeof((a).begin()) it = (a).begin(); it != (a).end(); it++)
#define sz(a) int((a).size())
#define present(t, x) (t.find(x) != t.end())
#define all(a) (a).begin(), (a).end()
#define uni(a) (a).erase(unique(all(a)), (a).end())
#define pb push_back
#define pf push_front
#define mp make_pair
#define fi first
#define se second
#define prec(n) fixed<<setprecision(n)
#define bit(n, i) (((n) >> (i)) & 1)
#define bitcount(n) __builtin_popcountll(n)
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<int, int> pi;
typedef vector<int> vi;
typedef vector<pi> vii;
//const int MOD = (int) 1e9 + 7;
const int MOD = 998244353;
const int FFTMOD = 1007681537;
const int INF = (int) 1e9;
const ll LINF = (ll) 1e18;
const ld PI = acos((ld) -1);
const ld EPS = 1e-9;
inline ll gcd(ll a, ll b) {ll r; while (b) {r = a % b; a = b; b = r;} return a;}
inline ll lcm(ll a, ll b) {return a / gcd(a, b) * b;}
inline ll fpow(ll n, ll k, int p = MOD) {ll r = 1; for (; k; k >>= 1) {if (k & 1) r = r * n % p; n = n * n % p;} return r;}
template<class T> inline int chkmin(T& a, const T& val) {return val < a ? a = val, 1 : 0;}
template<class T> inline int chkmax(T& a, const T& val) {return a < val ? a = val, 1 : 0;}
inline ll isqrt(ll k) {ll r = sqrt(k) + 1; while (r * r > k) r--; return r;}
inline ll icbrt(ll k) {ll r = cbrt(k) + 1; while (r * r * r > k) r--; return r;}
inline void addmod(int& a, int val, int p = MOD) {if ((a = (a + val)) >= p) a -= p;}
inline void submod(int& a, int val, int p = MOD) {if ((a = (a - val)) < 0) a += p;}
inline int mult(int a, int b, int p = MOD) {return (ll) a * b % p;}
inline int inv(int a, int p = MOD) {return fpow(a, p - 2, p);}
inline int sign(ld x) {return x < -EPS ? -1 : x > +EPS;}
inline int sign(ld x, ld y) {return sign(x - y);}
#define db(x) cerr << #x << " = " << (x) << " ";
#define endln cerr << "\n";

void chemthan() {
    int n, d1, d2; cin >> n >> d1 >> d2;
    vii vals;
    for (int i = 0; i * i <= d1; i++) {
        int j = isqrt(d1 - i * i);
        if (i * i + j * j == d1) {
            vals.pb(mp(i, j));
        }
    }
    for (int i = 0; i * i <= d2; i++) {
        int j = isqrt(d2 - i * i);
        if (i * i + j * j == d2) {
            vals.pb(mp(i, j));
        }
    }
    while (1)
    FOR(it, 0, 4) {
        vii pts;
        if (it == 0) {
        FOR(i, 0, n + n) FOR(j, 0, n + n) pts.pb(mp(i, j));
        }
        else if (it == 1) {
        FOR(i, 0, n + n) FORd(j, n + n, 0) pts.pb(mp(i, j));
        }
        else {
            vi vx; FOR(i, 0, n + n) vx.pb(i);
            random_shuffle(all(vx));
            FOR(i, 0, n + n) FOR(j, 0, n + n) pts.pb(mp(vx[i], vy[j]));
        }
        srand(time(NULL));
        static int f[605][605];
        ms(f, 0);
        vii fuck;
        FOR(i, 0, sz(pts)) {
            if (sz(fuck) == n * n) break;
            int x = pts[i].fi;
            int y = pts[i].se;
            if (f[x][y]) continue;
            fuck.pb(mp(x, y));
            f[x][y] = 1;
            for (auto it : vals) {
                int dx = it.fi;
                int dy = it.se;
                FOR(s1, -1, 1 + 1) FOR(s2, -1, 1 + 1) if (s1 && s2) {
                    int nx = x + dx * s1;
                    int ny = y + dy * s2;
                    if (0 <= nx && nx < 605 && 0 <= ny && ny < 605) {
                        f[nx][ny] = 1;
                    }
                }
            }
        }
        if (sz(fuck) == n * n) {
            for (auto it : fuck) {
                cout << it.fi << " " << it.se << "\n";
            }
            return;
        }
    }
}

int main(int argc, char* argv[]) {
    ios_base::sync_with_stdio(0), cin.tie(0);
    if (argc > 1) {
        assert(freopen(argv[1], "r", stdin));
    }
    if (argc > 2) {
        assert(freopen(argv[2], "wb", stdout));
    }
    chemthan();
    cerr << "\nTime elapsed: " << 1000 * clock() / CLOCKS_PER_SEC << "ms\n";
    return 0;
}


Compiler output:
a.cc: In function 'void chemthan()':
a.cc:77:27: warning: 'void std::random_shuffle(_RAIter, _RAIter) [with _RAIter = __gnu_cxx::__normal_iterator<int*, vector<int> >]' is deprecated: use 'std::shuffle' instead [-Wdeprecated-declarations]
   77 |             random_shuffle(all(vx));
      |             ~~~~~~~~~~~~~~^~~~~~~~~
In file included from /usr/include/c++/14/algorithm:61,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51,
                 from a.cc:1:
/usr/include/c++/14/bits/stl_algo.h:4492:5: note: declared here
 4492 |     random_shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last)
      |     ^~~~~~~~~~~~~~
a.cc:78:64: error: 'vy' was not declared in this scope; did you mean 'vx'?
   78 |             FOR(i, 0, n + n) FOR(j, 0, n + n) pts.pb(mp(vx[i], vy[j]));
      |                                                                ^~
      |                                                                vx