10071-Back to High School

呵呵哒…题目没看懂…生平第一次知道了displacement是位移的意思，还以为让我求两倍时间下速度的替代值…
这里用到了两个公式：

1. v = v0 + at
2. s = v0*t + 1/2*a*t^2

于是有 s’ = v0 * 2t + 1/2*a*(2t)^2 = 2v0*t + 2a*t^2 = 2t*(v0+at) = 2t*v

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题目:

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

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代码：

#include <stdio.h>int main() {    int v, t;    while (scanf("%d%d", &v, &t) == 2) {        printf("%d\n", 2 * v*t);    }    return 0;}