Language: C++

#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<cmath>
#include<string>
#include<cstring>
#include<algorithm>
#include<sstream>
#include<complex>
#include<functional>
#include<vector>
#include<map>
#include<queue>
#include<deque>
#include<stack>
#include<set>

using namespace std;
#define endl '\n'
#define eb emplace_back
#define fst first
#define scd second
#define EPS (1e-7)
#define INF (1e9)
#define PI (acos(-1))
#define YES(n) cout << ((n) ? "YES" : "NO" ) << endl
#define Yes(n) cout << ((n) ? "Yes" : "No" ) << endl

constexpr ll mod = 1000000007;

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<vector<int>> vii;
typedef vector<ll> vl;

ll gcd(ll a, ll b) { return b ? gcd(b, a%b) : a; }

// value
ll N, A, B, C;

ll fact[200020], fact_inv[200020];

// 繰り返し二乗法
ll power(ll a, ll b) {
	ll res = 1;
	while (b > 0) {
		if (b & 1) res = res * a%mod;
		a = a * a%mod;
		b >>= 1;
	}
	return res;
}

ll comb(ll n, ll r) {
	return (fact[n] * fact_inv[r]) % mod*fact_inv[n - r] % mod;
}

void calcComb() {
	const int num = 200020;
	fact[0] = 1;
	for (int i = 0; i < num; i++) {
		fact[i + 1] = fact[i] * ((ll)i + 1LL) % mod;
	}
	fact_inv[num] = power(fact[num], mod - 2);
	for (int i = num - 1; i >= 0; i--) {
		fact_inv[i] = fact_inv[i + 1] * (i + 1) % mod;
	}
}

// 逆元を求める
long long mod_inv(long long value) {

	long long b = mod, u = 1, v = 0;

	while (b) {
		long long t = value / b;
		value -= t * b;
		swap(value, b);
		u -= t * v;
		swap(u, v);
	}
	u %= mod;
	if (u < 0) u += mod;

	return u;
}

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

void solve() {

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

	calcComb();

	ll ans = 0;
	for (int M = N; M < 2 * N; M++) {
		ll X = comb(M - 1, N - 1) * ((mod_pow(A * mod_inv(100 - C) % mod, N) * mod_pow(B * mod_inv(100 - C) % mod, M - N) % mod + mod_pow(B * mod_inv(100 - C) % mod, N) * mod_pow(A * mod_inv(100 - C) % mod, M - N) % mod) % mod) % mod;
		ll Y = M * 100 % mod * mod_inv(100 - C) % mod;
		ans += X * Y % mod;
	}
	cout << ans % mod << endl;

	return;

}

int main() {

	cin.tie(0);
	ios::sync_with_stdio(false);

	solve();

	return 0;

}

Compiler output:
a.cc:29:11: error: 'll' does not name a type
   29 | constexpr ll mod = 1000000007;
      |           ^~
a.cc: In function 'll power(ll, ll)':
a.cc:49:42: error: 'mod' was not declared in this scope; did you mean 'modf'?
   49 |                 if (b & 1) res = res * a%mod;
      |                                          ^~~
      |                                          modf
a.cc:50:27: error: 'mod' was not declared in this scope; did you mean 'modf'?
   50 |                 a = a * a%mod;
      |                           ^~~
      |                           modf
a.cc: In function 'll comb(ll, ll)':
a.cc:57:42: error: 'mod' was not declared in this scope; did you mean 'modf'?
   57 |         return (fact[n] * fact_inv[r]) % mod*fact_inv[n - r] % mod;
      |                                          ^~~
      |                                          modf
a.cc: In function 'void calcComb()':
a.cc:64:57: error: 'mod' was not declared in this scope; did you mean 'modf'?
   64 |                 fact[i + 1] = fact[i] * ((ll)i + 1LL) % mod;
      |                                                         ^~~
      |                                                         modf
a.cc:66:42: error: 'mod' was not declared in this scope; did you mean 'modf'?
   66 |         fact_inv[num] = power(fact[num], mod - 2);
      |                                          ^~~
      |                                          modf
a.cc: In function 'long long int mod_inv(long long int)':
a.cc:75:23: error: 'mod' was not declared in this scope; did you mean 'modf'?
   75 |         long long b = mod, u = 1, v = 0;
      |                       ^~~
      |                       modf
a.cc:81:17: error: 'u' was not declared in this scope
   81 |                 u -= t * v;
      |                 ^
a.cc:81:26: error: 'v' was not declared in this scope
   81 |                 u -= t * v;
      |                          ^
a.cc:84:9: error: 'u' was not declared in this scope
   84 |         u %= mod;
      |         ^
a.cc: In function 'll mod_pow(ll, long long int)':
a.cc:94:44: error: 'mod' was not declared in this scope; did you mean 'modf'?
   94 |                 if (n & 1) res = res * a % mod;
      |                                            ^~~
      |                                            modf
a.cc:95:29: error: 'mod' was not declared in this scope; did you mean 'modf'?
   95 |                 a = a * a % mod;
      |                             ^~~
      |                             modf
a.cc: In function 'void solve()':
a.cc:109:78: error: 'mod' was not declared in this scope; did you mean 'modf'?
  109 |                 ll X = comb(M - 1, N - 1) * ((mod_pow(A * mod_inv(100 - C) % mod, N) * mod_pow(B * mod_inv(100 - C) % mod, M - N) % mod + mod_pow(B * mod_inv(100 - C) % mod, N) * mod_pow(A * mod_inv(100 - C) % mod, M - N) % mod) % mod) % mod;
      |                                                                              ^~~
      |                                                                              modf
a.cc:113:23: error: 'mod' was not declared in this scope; did you mean 'modf'?
  113 |         cout << ans % mod << endl;
      |                       ^~~
      |                       modf