10071-Back to High School Physics

A particle has initial velocity and constant acceleration. If its velocity after certain time is v then what will its displacement be in twice of that time?

 

Input

The input will contain two integers in each line. Each line makes one set of input. These two integers denote the value of v (-100 <= v <= 100) and t(0<=t<= 200) ( t means at the time the particle gains that velocity) 

 

Output

For each line of input print a single integer in one line denoting the displacement in double of that time.

 

Sample Input

0 0
5 12

Sample Output

0

120

解题思路：

高中的基本物理知识，由于是匀加速运动，路程=平均速度*时间。由于要求两倍时间后的路程，平均速度就是一倍时间时的速度，所以s=v*2*t。

AC代码：

#include<iostream>using namespace std;int main(){    int v, t;    while(cin>>v>>t)    {        cout<< v*t*2 << endl;//输出平均速度*总时间    }    return 0;}