Editorial for Đong gạo
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Submitting an official solution before solving the problem yourself is a bannable offence.
Submitting an official solution before solving the problem yourself is a bannable offence.
Công thức cơ bản
$$ \min \left\{ a + b \mid a, b \in \mathbb{Z}_{\geq 0},~5a + 3b = N \right\} = \min_{\substack{0 \leq a \leq \lfloor \frac{N}{5} \rfloor \\ }} \left\{ a + \frac{N - 5a}{3}|(N - 5a) \equiv 0 \pmod{3} \right\} $$
Đoạn giã code
for a = floor(N/5) down to 0:
if (N - 5*a) mod 3 == 0:
b = (N - 5*a)/3
return a + b
return -1
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