AtCoder Beginner Contest 207
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Problem Statement
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There is a container with $A$ cyan balls. Takahashi will do the following operation as many times as he likes (possibly zero times):
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- add
$B$cyan balls and$C$red balls into the container.
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Takahashi's objective is to reach a situation where the number of cyan balls in the container is at most $D$ times the number of red balls in it.
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Determine whether the objective is achievable. If it is achievable, find the minimum number of operations needed to achieve it.
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Constraints
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$1 \leq A,B,C,D \leq 10^5$- All values in input are integers.
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Input
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Input is given from Standard Input in the following format:
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A B C D翻译中…
Output
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If Takahashi's objective is achievable, print the minimum number of operations needed to achieve it. Otherwise, print -1.
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样例
Input #1
5 2 3 2
Output #1
2
Before the first operation, the container has $5$ cyan balls and $0$ red balls. Since $5$ is greater than $0$ multiplied by $D=2$, Takahashi's objective is not yet achieved.
Just after the first operation, the container has $7$ cyan balls and $3$ red balls. Since $7$ is greater than $3$ multiplied by $2$, the objective is still not achieved.
Just after the second operation, the container has $9$ cyan balls and $6$ red balls. Since $9$ is not greater than $6$ multiplied by $2$, the objective is achieved.
Thus, the answer is $2$.
Input #2
6 9 2 3
Output #2
-1
No matter how many times Takahashi repeats the operation, his objective will never be achieved.
题目信息
题面与样例版权归 AtCoder 及出题人所有；中文翻译由 AI 生成（CI 管线），如有出入请以原文为准。