Language: C++

#include <bits/stdc++.h>
using namespace std;
struct fast_ios { fast_ios(){ cin.tie(0); ios::sync_with_stdio(false); cout << fixed << setprecision(20); }; } fast_ios_;
#define FOR(i, begin, end) for(int i=(begin);i<(end);i++)
#define REP(i, n) FOR(i,0,n)
#define IFOR(i, begin, end) for(int i=(end)-1;i>=(begin);i--)
#define IREP(i, n) IFOR(i,0,n)
#define Sort(v) sort(v.begin(), v.end())
#define Reverse(v) reverse(v.begin(), v.end())
#define all(v) v.begin(),v.end()
#define SZ(v) ((int)v.size())
#define Lower_bound(v, x) distance(v.begin(), lower_bound(v.begin(), v.end(), x))
#define Upper_bound(v, x) distance(v.begin(), upper_bound(v.begin(), v.end(), x))
#define Max(a, b) a = max(a, b)
#define Min(a, b) a = min(a, b)
#define bit(n) (1LL<<(n))
#define bit_exist(x, n) ((x >> n) & 1)
#define debug(x) cout << #x << "=" << x << endl;
#define vdebug(v) cout << #v << "=" << endl; REP(i_debug, v.size()){ cout << v[i_debug] << ","; } cout << endl;
#define mdebug(m) cout << #m << "=" << endl; REP(i_debug, m.size()){ REP(j_debug, m[i_debug].size()){ cout << m[i_debug][j_debug] << ","; } cout << endl;}
#define pb push_back
#define f first
#define s second
#define int long long
#define INF 1000000000000000000
template<typename T> istream &operator>>(istream &is, vector<T> &v){ for (auto &x : v) is >> x; return is; }
template<typename T> ostream &operator<<(ostream &os, vector<T> &v){ for(int i = 0; i < v.size(); i++) { cout << v[i]; if(i != v.size() - 1) cout << endl; }; return os; }
template<typename T> void Out(T x) { cout << x << endl; }
template<typename T1, typename T2> void Ans(bool f, T1 y, T2 n) { if(f) Out(y); else Out(n); }

using vec = vector<int>;
using mat = vector<vec>;
using Pii = pair<int, int>;
using PiP = pair<int, Pii>;
using PPi = pair<Pii, int>;
using bools = vector<bool>;
using pairs = vector<Pii>;

//int dx[4] = {1,0,-1,0};
//int dy[4] = {0,1,0,-1};
//char d[4] = {'D','R','U','L'};

const int mod = 1000000007;
//const int mod = 998244353;
#define Add(x, y) x = (x + (y)) % mod
#define Mult(x, y) x = (x * (y)) % mod

bool calcv(int x, int n, int K, vec &v, int &nk){
    v.resize(0);
    int np = 0, nm = 0;
    REP(i, n){
        if(x == 0) break;
        else if(x >= K){
            np++;
            x -= K;
        }else if(x <= -K){
            nm--;
            x += K;
        }else if((x - K) % 2 == 0){
            v.pb(x);
            x = 0;
        }else if(x > 0){
            np++;
            x -= K;
        }else{
            nm++;
            x += K;
        }
    }
    if(x) return false;
    if((n - SZ(v)) % 2) v.pb(0);
    int tmp = (n - SZ(v)) / 2;
    np += tmp; nm += tmp;
    REP(i, np) v.pb(K);
    REP(i, nm) v.pb(-K);
    nk = np + nm;

    return true;
}

signed main(){

    int K; cin >> K;
    int X, Y; cin >> X >> Y;

    if(K % 2 == 0 && (X + Y) % 2 != 0){
        Out(-1);
        return 0;
    }

    int x = X + Y, y = X - Y;

    int ans = INF;

    int p = 0;
    int n0 = 0, n1 = bit(17);
    vec vx, vy;
    int nkx, nky;
    while(n1 - n0 > 1){
        int n = (n0 + n1) / 2;
        int N = 2 * n + p;
        bool fx = calcv(x, N, K, vx, nkx);
        bool fy = calcv(y, N, K, vy, nky);
        //debug(N);
        //vdebug(vx);
        if(fx && fy && nkx + nky >= N){
            Min(ans, N);
            n1 = n;
        }else n0 = n;
    }
    p = -1;
    n0 = 0, n1 = bit(17);
    while(n1 - n0 > 1){
        int n = (n0 + n1) / 2;
        int N = 2 * n + p;
        bool fx = calcv(x, N, K, vx, nkx);
        bool fy = calcv(y, N, K, vy, nky);
        if(fx && fy && nkx + nky >= N){
            Min(ans, N);
            n1 = n;
        }else n0 = n;
    }

    assert(ans < INF);
    Out(ans);
    bool fx = calcv(x, ans, K, vx, nkx);
    bool fy = calcv(y, ans, K, vy, nky);
    int tx = 0, ty = 0;
    REP(i, ans){
        int x0 = vx[i], y0 = vy[ans - 1 - i];
        int dx = (x0 + y0) / 2, dy += (x0 - y0) / 2;
        tx += dx;
        ty += dy;
        assert(llabs(dx) + llabs(dy) == K);
        cout << tx << " " << ty << endl;
    }

    return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:131:36: error: expected initializer before '+=' token
  131 |         int dx = (x0 + y0) / 2, dy += (x0 - y0) / 2;
      |                                    ^~
a.cc:133:15: error: 'dy' was not declared in this scope; did you mean 'dx'?
  133 |         ty += dy;
      |               ^~
      |               dx