ARC075-D

ARC075-D.cpp

#include <bits/stdc++.h>
using namespace std;

#define fs first
#define se second
#define all(v) v.begin(), v.end()
#define rep(i, n) for (int i = 0; i < n; ++i)
#define pb emplace_back

using pii = pair<int, int>;
using vi = vector<int>;
using lint = long long;

const int inf = 1001001001;
const lint linf = 1001001001001001001ll;
const int mod = 1e9 + 7;
const int dx[]{0, 1, 0, -1, -1, -1, 1, 1}, dy[]{1, 0, -1, 0, -1, 1, -1, 1};

template<typename T> inline bool chmin(T &a, T b) { if (a > b) { a = b; } return a > b; }
template<typename T> inline bool chmax(T &a, T b) { if (a < b) { a = b; } return a < b; }
template<typename T> inline void print(const T &x, string s = "\n") { cout << x << s; }
template<typename T> inline void print(const vector<T> &v, string s = " ") 
{ rep(i, v.size()) cout << v[i] << (i + 1 == v.size() ? "\n" : s); }
inline bool inside(int y, int x, int H, int W) { return 0 <= y && y < H && 0 <= x && x < W; }
inline lint in() { lint x; std::cin>>x; return x; }

vector<lint> h;
lint n;
lint a, b, d;

bool f(lint m) {
	lint cnt = 0;
	rep(i, n) {
		lint H = h[i] - m * b;
		if (H <= 0) continue;
		cnt += (H + d - 1) / d;
	}

	return cnt <= m;
}

int main() {
	cin >> n >> a >> b;
	d = a - b;

	lint s = 0;
	rep(i, n) { h.pb(in()); chmax(s, h[i]); }

	lint l = 0, r = s / b + 1000;
	while (r - l > 1) {
		lint m = (l + r) / 2;
		if (f(m)) {
			r = m;
		} else {
			l = m;
		}
	}

	if (!f(l)) {
		l = r;
	}

	cout << l << endl;
}