import sys
def input():
return sys.stdin.readline().strip()
def ispossible(make,n,k,a,b):
return make*a+b*(n-make)<k
for _ in range(int(input())):
k,n,a,b=map(int,input().split())
if n*b>=k:
print("-1")
continue
l=0
r=n
ans=0
while l<=r:
m= (r-l)//2 + l
if ispossible(m,n,k,a,b):
l=m+1
ans=m
else:
r=m-1
print(ans)
#include <iostream>
using namespace std;
long long int busca_binaria(long long int k, long long int n, long long int a, long long int b) {
long long int max = n, min = 0, meio, aux, result;
while (min <= max) {
meio = (min + max) / 2;
aux = n - meio;
if (meio * a + aux * b < k) {
result = meio;
min = meio + 1;
}
else if (meio * a + aux * b >= k)
max = meio - 1;
}
if (max != - 1)
return result;
else
return max;
}
int main() {
long long int consulta, k, n, a, b, aux;
cin >> consulta;
for (long long int i = 0; i < consulta; i++) {
cin >> k;
cin >> n;
cin >> a;
cin >> b;
printf("%lld\n", busca_binaria(k, n, a, b));
}
return 0;
}1025D - Recovering BST | 439A - Devu the Singer and Churu the Joker |
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