1902B - Getting Points - CodeForces Solution

#include <bits/stdc++.h>
#define speed ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
//#define sort sort(v.begin(),v.end());
//freopen("sets.in", "r", stdin);
using namespace std;
long long mod=1e9+7;
long long power(long long n, long long m)
{
    if (!m)return 1;
    if (m==1)return n%mod;
    long long lol=power(n,m/2);
    return (m&1?((((n%mod)*(lol%mod))%mod)*(lol%mod))%mod:((lol%mod)*(lol%mod))%mod);
}
long long ncr(long long n, long long m)
{
    if(m==0)return 1;
    return ((((n%mod)*(ncr(n-1,m-1)%mod))%mod)/m)%mod;
}
long long npr(long long n, long long r) {
	if (r > n)
		return 0;
	long long p = 1, i = n - r + 1;
	while (i <= n)
		p *= i++;
	return p;
}

bool prime(long long x)
{
    if (x<=1)return 0;
    for (int i=2; i<=sqrt(x); i++)
        if (!(x%i))
            return 0;
    return 1;
}
long long fact(long long a)
{
    if (!a)return 1; return (a == 1 ? 1 : fact(a - 1) * a);
}
int main()
{

    speed
    //coming..soon

    int t=1;
    cin>>t;
    while(t--){
      long long n, p, l, t;
      cin >> n >> p >> l >> t;
      long long total =(n+6)/7 ;
      long long st = 0, ed = n;
      while (st<ed)
      {
        long long mi = (st + ed + 1) / 2;
        long long sum = (n - mi) * l + t * min(total, (n - mi) * 2ll);
        if (sum >= p) st = mi;
        else ed = mi - 1;
      }
      cout <<st<< "\n";
    }

    return 0;

}