题库练习 Greedy Arkady
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A11700 | Greedy Arkady

时间限制1s
内存限制256MB
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题目描述

$k$ people want to split $n$ candies between them. Each candy should be given to exactly one of them or be thrown away.

The people are numbered from $1$ to $k$ , and Arkady is the first of them. To split the candies, Arkady will choose an integer $x$ and then give the first $x$ candies to himself, the next $x$ candies to the second person, the next $x$ candies to the third person and so on in a cycle. The leftover (the remainder that is not divisible by $x$ ) will be thrown away.

Arkady can't choose $x$ greater than $M$ as it is considered greedy. Also, he can't choose such a small $x$ that some person will receive candies more than $D$ times, as it is considered a slow splitting.

Please find what is the maximum number of candies Arkady can receive by choosing some valid $x$ .

输入格式

The only line contains four integers $n$ , $k$ , $M$ and $D$ ( $2 \le n \le 10^{18}$ , $2 \le k \le n$ , $1 \le M \le n$ , $1 \le D \le \min{(n, 1000)}$ , $M \cdot D \cdot k \ge n$ ) — the number of candies, the number of people, the maximum number of candies given to a person at once, the maximum number of times a person can receive candies.

输出格式

Print a single integer — the maximum possible number of candies Arkady can give to himself.

Note that it is always possible to choose some valid $x$ .

输入输出样例

输入 #1
20 4 5 2
输出 #1
8
输入 #2
30 9 4 1
输出 #2
4
C++ 编辑器
输入
输出