Problem p03027 (C++)

Buggy submission (status: Runtime Error):
#include <algorithm>
#include <bitset>
#include <cctype>
#include <cmath>
#include <cstdint>
#include <cstdio>
#include <ctime>
#include <deque>
#include <float.h>
#include <functional>
#include <iomanip>
#include <iostream>
#include <limits>
#include <map>
#include <math.h>
#include <numeric>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <tuple>
#include <type_traits>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>
using namespace std;
using ll = long long;
unsigned euclidean_gcd(unsigned a, unsigned b) {
  if (a < b)
    return euclidean_gcd(b, a);
  unsigned r;
  while ((r = a % b)) {
    a = b;
    b = r;
  }
  return b;
}

ll ll_gcd(ll a, ll b) {
  if (a < b)
    return ll_gcd(b, a);
  ll r;
  while ((r = a % b)) {
    a = b;
    b = r;
  }
  return b;
}

struct UnionFind {
  vector<ll> par;
  vector<ll> siz;
  UnionFind(ll sz_) : par(sz_), siz(sz_, 1LL) {
    for (ll i = 0; i < sz_; ++i)
      par[i] = i;
  }
  void init(ll sz_) {
    par.resize(sz_);
    siz.assign(sz_, 1LL);
    for (ll i = 0; i < sz_; ++i)
      par[i] = i;
  }
  ll root(ll x) {
    while (par[x] != x) {
      x = par[x] = par[par[x]];
    }
    return x;
  }
  bool merge(ll x, ll y) {
    x = root(x);
    y = root(y);
    if (x == y)
      return false;
    if (siz[x] < siz[y])
      swap(x, y);
    siz[x] += siz[y];
    par[y] = x;
    return true;
  }

  bool issame(ll x, ll y) { return root(x) == root(y); }

  ll size(ll x) { return siz[root(x)]; }
};

long long modpow(long long a, long long n, long long mod) {
  long long res = 1;
  while (n > 0) {
    if (n & 1)
      res = res * a % mod;
    a = a * a % mod;
    n >>= 1;
  }
  return res;
}

long long modinv(long long a, long long mod) { return modpow(a, mod - 2, mod); }

vector<int> tpsort(vector<vector<int>> &G) {
  int V = G.size();
  vector<int> sorted_vertices;
  queue<int> que;
  vector<int> indegree(V);
  for (int i = 0; i < V; i++) {
    for (int j = 0; j < G[i].size(); j++) {
      indegree[G[i][j]]++;
    }
  }
  for (int i = 0; i < V; i++) {
    if (indegree[i] == 0) {
      que.push(i);
    }
  }
  while (que.empty() == false) {
    int v = que.front();
    que.pop();
    for (int i = 0; i < G[v].size(); i++) {
      int u = G[v][i];
      indegree[u] -= 1;
      if (indegree[u] == 0)
        que.push(u);
    }
    sorted_vertices.push_back(v);
  }
  return sorted_vertices;
}

struct Point {
  double x;
  double y;
};

struct LineSegment {
  Point start;
  Point end;
};

double tenkyori(const LineSegment &line, const Point &point) {
  double x0 = point.x, y0 = point.y;
  double x1 = line.start.x, y1 = line.start.y;
  double x2 = line.end.x, y2 = line.end.y;

  double a = x2 - x1;
  double b = y2 - y1;
  double a2 = a * a;
  double b2 = b * b;
  double r2 = a2 + b2;
  double tt = -(a * (x1 - x0) + b * (y1 - y0));

  if (tt < 0)
    return sqrt((x1 - x0) * (x1 - x0) + (y1 - y0) * (y1 - y0));
  else if (tt > r2)
    return sqrt((x2 - x0) * (x2 - x0) + (y2 - y0) * (y2 - y0));

  double f1 = a * (y1 - y0) - b * (x1 - x0);
  return sqrt((f1 * f1) / r2);
}

template <typename X> struct SegTree {
  using FX = function<X(X, X)>; // X•X -> X となる関数の型
  int n;
  FX fx;
  const X ex;
  vector<X> dat;
  SegTree(int n_, FX fx_, X ex_) : n(), fx(fx_), ex(ex_), dat(n_ * 4, ex_) {
    int x = 1;
    while (n_ > x) {
      x *= 2;
    }
    n = x;
  }

  void set(int i, X x) { dat[i + n - 1] = x; }
  void build() {
    for (int k = n - 2; k >= 0; k--)
      dat[k] = fx(dat[2 * k + 1], dat[2 * k + 2]);
  }

  void update(int i, X x) {
    i += n - 1;
    dat[i] = x;
    while (i > 0) {
      i = (i - 1) / 2; // parent
      dat[i] = fx(dat[i * 2 + 1], dat[i * 2 + 2]);
    }
  }

  X query(int a, int b) { return query_sub(a, b, 0, 0, n); }
  X query_sub(int a, int b, int k, int l, int r) {
    if (r <= a || b <= l) {
      return ex;
    } else if (a <= l && r <= b) {
      return dat[k];
    } else {
      X vl = query_sub(a, b, k * 2 + 1, l, (l + r) / 2);
      X vr = query_sub(a, b, k * 2 + 2, (l + r) / 2, r);
      return fx(vl, vr);
    }
  }
};

template <typename X, typename M> struct SegTreeLazy {
  using FX = function<X(X, X)>;
  using FA = function<X(X, M)>;
  using FM = function<M(M, M)>;
  int n;
  FX fx;
  FA fa;
  FM fm;
  const X ex;
  const M em;
  vector<X> dat;
  vector<M> lazy;
  SegTreeLazy(int n_, FX fx_, FA fa_, FM fm_, X ex_, M em_)
      : n(), fx(fx_), fa(fa_), fm(fm_), ex(ex_), em(em_), dat(n_ * 4, ex),
        lazy(n_ * 4, em) {
    int x = 1;
    while (n_ > x)
      x *= 2;
    n = x;
  }

  void set(int i, X x) { dat[i + n - 1] = x; }
  void build() {
    for (int k = n - 2; k >= 0; k--)
      dat[k] = fx(dat[2 * k + 1], dat[2 * k + 2]);
  }

  void eval(int k) {
    if (lazy[k] == em)
      return;
    if (k < n - 1) {
      lazy[k * 2 + 1] = fm(lazy[k * 2 + 1], lazy[k]);
      lazy[k * 2 + 2] = fm(lazy[k * 2 + 2], lazy[k]);
    }

    dat[k] = fa(dat[k], lazy[k]);
    lazy[k] = em;
  }

  void update(int a, int b, M x, int k, int l, int r) {
    eval(k);
    if (a <= l && r <= b) {
      lazy[k] = fm(lazy[k], x);
      eval(k);
    } else if (a < r && l < b) {
      update(a, b, x, k * 2 + 1, l, (l + r) / 2);
      update(a, b, x, k * 2 + 2, (l + r) / 2, r);
      dat[k] = fx(dat[k * 2 + 1], dat[k * 2 + 2]);
    }
  }
  void update(int a, int b, M x) { update(a, b, x, 0, 0, n); }

  X query_sub(int a, int b, int k, int l, int r) {
    eval(k);
    if (r <= a || b <= l) {
      return ex;
    } else if (a <= l && r <= b) {
      return dat[k];
    } else {
      X vl = query_sub(a, b, k * 2 + 1, l, (l + r) / 2);
      X vr = query_sub(a, b, k * 2 + 2, (l + r) / 2, r);
      return fx(vl, vr);
    }
  }
  X query(int a, int b) { return query_sub(a, b, 0, 0, n); }
};

int main() {
  ll q;
  cin >> q;
  vector<ll> bik(2002008);
  bik[0] = 1;
  for (int i = 0; i < 2000104; i++) {
    bik[i + 1] = (i + 1) * bik[i] % 1000003;
  }
  for (int i = 0; i < q; i++) {
    ll a, b, c;
    cin >> a >> b >> c;
    ll d = modinv(b, 1000003) * a % 1000003;
    ll ans = bik[d + c - 1] * modinv(bik[d - 1], 1000003) % 1000003 *
             modpow(b, c, 1000003) % 1000003;
    cout << ans << endl;
  }
}

Fixed submission:
#include <algorithm>
#include <bitset>
#include <cctype>
#include <cmath>
#include <cstdint>
#include <cstdio>
#include <ctime>
#include <deque>
#include <float.h>
#include <functional>
#include <iomanip>
#include <iostream>
#include <limits>
#include <map>
#include <math.h>
#include <numeric>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <tuple>
#include <type_traits>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>
using namespace std;
using ll = long long;
unsigned euclidean_gcd(unsigned a, unsigned b) {
  if (a < b)
    return euclidean_gcd(b, a);
  unsigned r;
  while ((r = a % b)) {
    a = b;
    b = r;
  }
  return b;
}

ll ll_gcd(ll a, ll b) {
  if (a < b)
    return ll_gcd(b, a);
  ll r;
  while ((r = a % b)) {
    a = b;
    b = r;
  }
  return b;
}

struct UnionFind {
  vector<ll> par;
  vector<ll> siz;
  UnionFind(ll sz_) : par(sz_), siz(sz_, 1LL) {
    for (ll i = 0; i < sz_; ++i)
      par[i] = i;
  }
  void init(ll sz_) {
    par.resize(sz_);
    siz.assign(sz_, 1LL);
    for (ll i = 0; i < sz_; ++i)
      par[i] = i;
  }
  ll root(ll x) {
    while (par[x] != x) {
      x = par[x] = par[par[x]];
    }
    return x;
  }
  bool merge(ll x, ll y) {
    x = root(x);
    y = root(y);
    if (x == y)
      return false;
    if (siz[x] < siz[y])
      swap(x, y);
    siz[x] += siz[y];
    par[y] = x;
    return true;
  }

  bool issame(ll x, ll y) { return root(x) == root(y); }

  ll size(ll x) { return siz[root(x)]; }
};

long long modpow(long long a, long long n, long long mod) {
  long long res = 1;
  while (n > 0) {
    if (n & 1)
      res = res * a % mod;
    a = a * a % mod;
    n >>= 1;
  }
  return res;
}

long long modinv(long long a, long long mod) { return modpow(a, mod - 2, mod); }

vector<int> tpsort(vector<vector<int>> &G) {
  int V = G.size();
  vector<int> sorted_vertices;
  queue<int> que;
  vector<int> indegree(V);
  for (int i = 0; i < V; i++) {
    for (int j = 0; j < G[i].size(); j++) {
      indegree[G[i][j]]++;
    }
  }
  for (int i = 0; i < V; i++) {
    if (indegree[i] == 0) {
      que.push(i);
    }
  }
  while (que.empty() == false) {
    int v = que.front();
    que.pop();
    for (int i = 0; i < G[v].size(); i++) {
      int u = G[v][i];
      indegree[u] -= 1;
      if (indegree[u] == 0)
        que.push(u);
    }
    sorted_vertices.push_back(v);
  }
  return sorted_vertices;
}

struct Point {
  double x;
  double y;
};

struct LineSegment {
  Point start;
  Point end;
};

double tenkyori(const LineSegment &line, const Point &point) {
  double x0 = point.x, y0 = point.y;
  double x1 = line.start.x, y1 = line.start.y;
  double x2 = line.end.x, y2 = line.end.y;

  double a = x2 - x1;
  double b = y2 - y1;
  double a2 = a * a;
  double b2 = b * b;
  double r2 = a2 + b2;
  double tt = -(a * (x1 - x0) + b * (y1 - y0));

  if (tt < 0)
    return sqrt((x1 - x0) * (x1 - x0) + (y1 - y0) * (y1 - y0));
  else if (tt > r2)
    return sqrt((x2 - x0) * (x2 - x0) + (y2 - y0) * (y2 - y0));

  double f1 = a * (y1 - y0) - b * (x1 - x0);
  return sqrt((f1 * f1) / r2);
}

template <typename X> struct SegTree {
  using FX = function<X(X, X)>; // X•X -> X となる関数の型
  int n;
  FX fx;
  const X ex;
  vector<X> dat;
  SegTree(int n_, FX fx_, X ex_) : n(), fx(fx_), ex(ex_), dat(n_ * 4, ex_) {
    int x = 1;
    while (n_ > x) {
      x *= 2;
    }
    n = x;
  }

  void set(int i, X x) { dat[i + n - 1] = x; }
  void build() {
    for (int k = n - 2; k >= 0; k--)
      dat[k] = fx(dat[2 * k + 1], dat[2 * k + 2]);
  }

  void update(int i, X x) {
    i += n - 1;
    dat[i] = x;
    while (i > 0) {
      i = (i - 1) / 2; // parent
      dat[i] = fx(dat[i * 2 + 1], dat[i * 2 + 2]);
    }
  }

  X query(int a, int b) { return query_sub(a, b, 0, 0, n); }
  X query_sub(int a, int b, int k, int l, int r) {
    if (r <= a || b <= l) {
      return ex;
    } else if (a <= l && r <= b) {
      return dat[k];
    } else {
      X vl = query_sub(a, b, k * 2 + 1, l, (l + r) / 2);
      X vr = query_sub(a, b, k * 2 + 2, (l + r) / 2, r);
      return fx(vl, vr);
    }
  }
};

template <typename X, typename M> struct SegTreeLazy {
  using FX = function<X(X, X)>;
  using FA = function<X(X, M)>;
  using FM = function<M(M, M)>;
  int n;
  FX fx;
  FA fa;
  FM fm;
  const X ex;
  const M em;
  vector<X> dat;
  vector<M> lazy;
  SegTreeLazy(int n_, FX fx_, FA fa_, FM fm_, X ex_, M em_)
      : n(), fx(fx_), fa(fa_), fm(fm_), ex(ex_), em(em_), dat(n_ * 4, ex),
        lazy(n_ * 4, em) {
    int x = 1;
    while (n_ > x)
      x *= 2;
    n = x;
  }

  void set(int i, X x) { dat[i + n - 1] = x; }
  void build() {
    for (int k = n - 2; k >= 0; k--)
      dat[k] = fx(dat[2 * k + 1], dat[2 * k + 2]);
  }

  void eval(int k) {
    if (lazy[k] == em)
      return;
    if (k < n - 1) {
      lazy[k * 2 + 1] = fm(lazy[k * 2 + 1], lazy[k]);
      lazy[k * 2 + 2] = fm(lazy[k * 2 + 2], lazy[k]);
    }

    dat[k] = fa(dat[k], lazy[k]);
    lazy[k] = em;
  }

  void update(int a, int b, M x, int k, int l, int r) {
    eval(k);
    if (a <= l && r <= b) {
      lazy[k] = fm(lazy[k], x);
      eval(k);
    } else if (a < r && l < b) {
      update(a, b, x, k * 2 + 1, l, (l + r) / 2);
      update(a, b, x, k * 2 + 2, (l + r) / 2, r);
      dat[k] = fx(dat[k * 2 + 1], dat[k * 2 + 2]);
    }
  }
  void update(int a, int b, M x) { update(a, b, x, 0, 0, n); }

  X query_sub(int a, int b, int k, int l, int r) {
    eval(k);
    if (r <= a || b <= l) {
      return ex;
    } else if (a <= l && r <= b) {
      return dat[k];
    } else {
      X vl = query_sub(a, b, k * 2 + 1, l, (l + r) / 2);
      X vr = query_sub(a, b, k * 2 + 2, (l + r) / 2, r);
      return fx(vl, vr);
    }
  }
  X query(int a, int b) { return query_sub(a, b, 0, 0, n); }
};

int main() {
  ll q;
  cin >> q;
  vector<ll> bik(2002008);
  bik[0] = 1;
  for (int i = 0; i < 2000104; i++) {
    bik[i + 1] = (i + 1) * bik[i] % 1000003;
  }
  for (int i = 0; i < q; i++) {
    ll a, b, c;
    cin >> a >> b >> c;
    if (b == 0) {
      cout << modpow(a, c, 1000003) << endl;
      continue;
    }
    if (c >= 1000003) {
      cout << 0 << endl;
      continue;
    }
    ll d = modinv(b, 1000003) * a % 1000003;
    ll ans = bik[d + c - 1] * modinv(bik[d - 1], 1000003) % 1000003 *
             modpow(b, c, 1000003) % 1000003;
    cout << ans << endl;
  }
}