Victor and Machine----（BestCoder Round #52 (div.2)）

Victor and Machine

 Time Limit: 2000/1000 MS (Java/Others)

 

 Memory Limit: 131072/65536 K (Java/Others)

Problem Description

Victor has a machine. When the machine starts up, it will pop out a ball immediately. After that, the machine will pop out a ball every $w$ seconds. However, the machine has some flaws, every time after $x$ seconds of process the machine has to turn off for $y$ seconds for maintenance work. At the second the machine will be shut down, it may pop out a ball. And while it's off, the machine will pop out no ball before the machine restart.

Now, at the $0$ second, the machine opens for the first time. Victor wants to know when the $n$-th ball will be popped out. Could you tell him?

Input

The input contains several test cases, at most $100$ cases.

Each line has four integers $x$, $y$, $w$ and $n$. Their meanings are shown above。

$1\le x,y,w,n\le 100$.

Output

For each test case, you should output a line contains a number indicates the time when the $n$-th ball will be popped out.

Sample Input

2 3 3 3
98 76 54 32
10 9 8 100

Sample Output

10
2664
939

分析：直接模拟就行，最好把第一次开启时排除，然后捆绑先关闭和后开启。这样算起来方便些。

很遗憾，这次没在状态，只完成了一题。掉分了，还有codeforces也掉了，呜呜··

CODE：

#include <iostream>
using namespace std;

int main()
{
    long long x,y,w,n;
    while(cin>>x>>y>>w>>n){
        long long t=x/w+1;
        long long tim;
        if(n%t==0){
            tim=(n/t-1)*(x+y)+(t-1)*w;
        }
        else{
            tim=(n/t)*(x+y)+(n%t-1)*w;
        }
        cout<<tim<<endl;
    }
    return 0;
}