Language: C++

// #include <bits/stdc++.h>
#include <iostream> // cin, cout, string
#include <algorithm> // sort, min, max
#include <vector>
#include <utility> // pair, swap
#include <functional>
#include <iomanip> // setprecision
#include <map>
#include <set> // multiset
#include <unordered_map>
#include <unordered_set>
#include <tuple>
#include <stack>
#include <queue> // priority_queue
#include <deque>
#include <bitset>
#include <complex>
#include <ratio>

using namespace std;

// #define int long long

using ll = long long;
using ld = long double;

// template<class T1, class T2> using P = pair<T1, T2>;
template<class T> using vec = vector<T>;
template<class T> using mat = vec<vec<T>>;
template<typename T> using func = function<T>;

using pii = pair<int, int>;
using ppi = pair<pii, int>;
using pip = pair<int, pii>;
using ppp = pair<pii, pii>;

using vi = vec<int>;
using mi = mat<vi>; // Graph
using vp = vec<pii>;

constexpr int IINF =  0x3f3f3f3f;
constexpr long long LINF = 0x3f3f3f3f3f3f3f3fLL;
// constexpr int INF = sizeof(int) == sizeof(long long) ? LINF : IINF;
constexpr long long MOD = 1e9+7;

#define for_(i, a, b) for(int i = (a);i < (b);++i)
#define rfor_(i, a, b) for(int i = (b)-1;i >= (a);--i)

#define rep(i, n) for_(i, 0, n)
#define rrep(i, n) rfor_(i, 0, n)

#define pb push_back
// make_pair(A, B) == pair<T, U>(A, B)
#define mp make_pair
// tie(...) == mt(...)
#define mt make_tuple
// emplace_back(*) == push_back(constructor(*))
#define eb emplace_back
#define ft first
#define sd second

#define all(a) (a).begin(), (a).end()
#define rall(a) (a).rbegin(), (a).rend()
#define sz(a) (int)(a).size()
#define rev(a) reverse(all(a))
// #define sum(...) accumulate(range(__VA_ARGS__), 0LL)

#define endl '\n'
#define dec(n) fixed << setprecision(n)
#define zfl(n)  setfill(‘0’) << setw(n)
#define debug(x) cerr << #x << ": " << (x) << endl

template<typename T> T gcd(T a, T b) { if(a==0 || b==0) return 0; while(b) { a = a%b; swap(a, b); } return a; }
template<typename T> T lcm(T a, T b) { return a / gcd(a, b) * b; }

template<class T> bool chmax(T &a, const T &b) { if (a < b) { a = b; return true; } return false; }
template<class T> bool chmin(T &a, const T &b) { if (b < a) { a = b; return true; } return false; }

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, const vector<T> &v) { for(int i=0; i<(int)v.size(); ++i) cout << v[i] << ( i+1 != (int)v.size() ? " " : "" ); return os; }

template<typename A, typename B> istream &operator>>(istream &is, pair<A, B> &p) { is >> p.first; is >> p.second; return is; }
template<typename A, typename B> ostream &operator<<(ostream &os, const pair<A, B> &p) { os << p.first << " " << p.second; return os; }

inline auto yes(const bool &i) { return i ? "yes" : "no"; }
inline auto Yes(const bool &i) { return i ? "Yes" : "No"; }
inline auto YES(const bool &i) { return i ? "YES" : "NO"; }
inline auto Possible(const bool &i){ return i ? "Possible" : "Impossible"; }
inline auto POSSIBLE(const bool &i){ return i ? "POSSIBLE" : "IMPOSSIBLE"; }

const int limit = 100007; // 10^5+7

template<typename T=long long, const T P=(T)MOD> // P : prime
class Zp {
  private:
    T n;
    template<typename U> void set(const U &m) { n = (m % mod + mod) % mod; }
    void set(const Zp &m) { n = m.get(); }
  public:
    static const T mod;
    template<typename U> static Zp inv(const U &m) {
      T a = m, b = mod, u = 1, v = 0; // u = pow(a, mod-2), extgcd(a, b, u, v)
      while (b) {
        T t = a / b;
        a -= t * b; swap(a, b);
        u -= t * v; swap(u, v);
      }
      assert( a == 1 ); // gcd(a, b) == 1
      return Zp(u);
    }
    static Zp inv(const Zp &m) { return inv(m.get()); }
    Zp() : n(0) {}
    Zp(const Zp &m) : n(m.get()) {}
    template<typename U> Zp(U m) { set(m); }
    T get() const { return n; }
    T abs() const { return 2*n > mod ? n-mod : n; }
    Zp &operator=(const Zp &m) { set(m); return *this; }
    template<typename U> Zp &operator=(const U &m) { set(m); return *this; }
    template<typename U> Zp &operator+=(const U &m) { set(n+m); return *this; }
    Zp &operator+=(const Zp &m) { set(n+m.get()); return *this; }
    template<typename U> Zp &operator-=(const U &m) { set(n-m); return *this; }
    Zp &operator-=(const Zp &m) { set(n-m.get()); return *this; }
    template<typename U> Zp &operator*=(const U &m) { set(n * (m % mod)); return *this; }
    Zp &operator*=(const Zp &m) { set(n * m.get()); return *this; }
    template<typename U> Zp &operator/=(const U &m) { set(n * inv(m % mod)); return *this; }
    Zp &operator/=(const Zp &m) { set(n * inv(m.get())); return *this; }
    template<typename U> Zp pow(U e) const {
      if(e==0) return Zp(1);
      else if(e < 0) return inv(pow(-e));
      else {
        Zp a = *this, r = 1;
        while (e > 0) {
          if (e & 1) r *= a;
          a *= a;
          e >>= 1;
        }
        return r;
      }
    }
    template<typename U> Zp operator^(U m) const { return pow(m); }
    operator T() const { return n; }
};
template<typename T, T P> const T Zp<T, P>::mod = P;
template<typename T, T P> const Zp<T, P> operator+(const Zp<T, P> &n, const Zp<T, P> &m) { return Zp<T, P>(n) += m; }
template<typename T, T P, typename U> const Zp<T, P> operator+(const Zp<T, P> &n, const U &m) { return Zp<T, P>(n) += m; }
template<typename T, T P, typename U> const Zp<T, P> operator+(const U &n, const Zp<T, P> &m) { return Zp<T, P>(n) += m; }
template<typename T, T P> const Zp<T, P> operator-(const Zp<T, P> &n, const Zp<T, P> &m) { return Zp<T, P>(n) -= m; }
template<typename T, T P, typename U> const Zp<T, P> operator-(const Zp<T, P> &n, const U &m) { return Zp<T, P>(n) -= m; }
template<typename T, T P, typename U> const Zp<T, P> operator-(const U &n, const Zp<T, P> &m) { return Zp<T, P>(n) -= m; }
template<typename T, T P> const Zp<T, P> operator*(const Zp<T, P> &n, const Zp<T, P> &m) { return Zp<T, P>(n) *= m; }
template<typename T, T P, typename U> const Zp<T, P> operator*(const Zp<T, P> &n, const U &m) { return Zp<T, P>(n) *= m; }
template<typename T, T P, typename U> const Zp<T, P> operator*(const U &n, const Zp<T, P> &m) { return Zp<T, P>(n) *= m; }
template<typename T, T P> const Zp<T, P> operator/(const Zp<T, P> &n, const Zp<T, P> &m) { return Zp<T, P>(n) /= m; }
template<typename T, T P, typename U> const Zp<T, P> operator/(const Zp<T, P> &n, const U &m) { return Zp<T, P>(n) /= m; }
template<typename T, T P, typename U> const Zp<T, P> operator/(const U &n, const Zp<T, P> &m) { return Zp<T, P>(n) /= m; }
template<typename T, T P> istream &operator>>(istream &is, Zp<T, P> &n) { T m; is >> m; n = m; return is; }
template<typename T, T P> ostream &operator<<(ostream &os, const Zp<T, P> &n) { os << n.get(); return os; }

template<typename T=long long, const T P=(T)MOD>
class COM {
  private:
  int m;
  vector<Zp<T, P>> fac, finv, inv;
  void init(const int &n) {
    if(m >= n) return ;
    fac.resize(n+1);
    inv.resize(n+1);
    finv.resize(n+1);
    for (int i = m+1; i <= n; i++){
      fac[i] = fac[i - 1] * i;
      inv[i] = P - inv[P % i] * (P / i);
      finv[i] = finv[i - 1] * inv[i];
    }
    m = n;
  }
  public:
  COM() : m(1), fac(2, 1), finv(2, 1), inv(2, 1) {}
  COM(const int &n) : m(1), fac(2, 1), finv(2, 1), inv(2, 1) { init(n); }
  Zp<T, P> operator()(const int &n, const int &k) {
    if (n < k) return Zp<T, P>(0);
    if (n < 0 || k < 0) return Zp<T, P>(0);
    init(n);
    return fac[n] * (finv[k] * finv[n - k]);
  }
};

using Mod = Zp<>;

int N;
Mod A, B, C;
Mod a[limit], b[limit], c;
COM<> com;

signed main() {
  cin.tie(0);cout.tie(0);
  ios_base::sync_with_stdio(false);

  cin >> N >> A >> B >> C;

  A /= 100-C;
  B /= 100-C;
  C /= 100;

  a[0] = b[0] = 1;
  rep(i, N) a[i+1] = a[i] * A;
  rep(i, N) b[i+1] = b[i] * B;

  Mod P = 0, Q = 1 - C;
  rep(i, N) P += com(N+i-1, i) * (a[N]*b[i] + a[i]*b[N]) * (N+i);

  // cout << P << '/' << Q << " = ";
  cout << P/Q << endl;

  return 0;
}


Compiler output:
a.cc:70:25: error: extended character ‘ is not valid in an identifier
   70 | #define zfl(n)  setfill(‘0’) << setw(n)
      |                         ^
a.cc:70:25: error: extended character ’ is not valid in an identifier
a.cc: In instantiation of 'static Zp<T, P> Zp<T, P>::inv(const U&) [with U = long long int; T = long long int; T P = 1000000007]':
a.cc:126:46:   required from 'Zp<T, P>& Zp<T, P>::operator/=(const Zp<T, P>&) [with T = long long int; T P = 1000000007]'
  126 |     Zp &operator/=(const Zp &m) { set(n * inv(m.get())); return *this; }
      |                                           ~~~^~~~~~~~~
a.cc:200:12:   required from here
  200 |   A /= 100-C;
      |            ^
a.cc:108:13: error: 'assert' was not declared in this scope
  108 |       assert( a == 1 ); // gcd(a, b) == 1
      |       ~~~~~~^~~~~~~~~~
a.cc:19:1: note: 'assert' is defined in header '<cassert>'; this is probably fixable by adding '#include <cassert>'
   18 | #include <ratio>
  +++ |+#include <cassert>
   19 |