D - Widespread
对二分答案的特点要敏感!!!
// https://atcoder.jp/contests/abc063/tasks/arc075_b
// 二分答案
#include <iostream>
#include <algorithm>
#include <queue>
using namespace std;
typedef long long LL;
const int N = 1e5 + 10;
int h[N];
int n, a, b;
bool check(int x)
{
int cnt = 0;
for (int i = 1; i <= n; i ++)
{
if (1ll*x*b < h[i])
{
cnt += (h[i] - x*b + (a-b-1)) / (a-b); // 注意这里是a-b, 而不是除a
}
if (cnt > x) return false;
}
return true;
}
void solv()
{
cin >> n >> a >> b;
int maxh = 0;
for (int i = 1; i <= n; i ++) {
cin >> h[i];
maxh = max(maxh, h[i]);
}
int l = 0, r = maxh;
while (l < r)
{
int mid = (l + r) / 2;
if (check(mid)) r = mid;
else l = mid + 1;
// cout << l << "," << r << endl;
}
cout << l << endl;
}
int main()
{
ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
int T = 1;
// cin >> T;
while (T --)
{
solv();
}
return 0;
}