题解 | #小红刷怪#

#include <iostream>
#include <algorithm>
#include <cmath>

using LL = long long;
using namespace std;

LL a,b,x,y;

LL ceil_div(LL n,LL m)
{
    if(n <= 0) return 0;
    return (n + m -1) / m;  
}

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    
    if(!(cin >> a >> b >> x >> y)) return 0;
    
    LL min_ops{-1};//最小操作数
    LL maxk = max((ceil_div(a, y)) , (ceil_div(b,y)));
    
    for(int i = 0; i <= maxk ;i++)
    {
        LL rem_a = a - i * y;
        LL rem_b = b - i * y;
    
        LL ops_a = ceil_div(rem_a , x);
        LL ops_b = ceil_div(rem_b , x);
        
        LL ops = ops_a + ops_b + i;
        if(ops < min_ops || min_ops == -1)
            min_ops = ops;
        
        if(rem_a <= 0 && rem_b <= 0)
            break;
    
    }
  
    cout << min_ops << "\n";
    
    return 0;
}