关于java：如何计算大数字的行进距离？

How could we calculate traveled distance, with big numbers?

我目前正在解决此kata："我要走多远？"！

说明说：

You have recently discovered that horses travel in a unique pattern -
they're either running (at top speed) or resting (standing still).

Here's an example of how one particular horse might travel:

The horse Blaze can run at 14 metres/second for 60 seconds, but must
then rest for 45 seconds.

After 500 seconds Blaze will have traveled 4200 metres.

Your job is to write a function that returns how long a horse will
have traveled after a given time.

输入：

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totalTime - How long the horse will be traveling (in seconds)

runTime - How long the horse can run for before having to rest (in seconds)

restTime - How long the horse have to rest for after running (in seconds)

speed - The max speed of the horse (in metres/second)

我已经手工完成了演算：

给出：速度= 14，运行时间= 60，rest时间= 45，总时间= 500

->要计算马跑多少时间，我们计算以下内容：

totalTime /(runTime restTime)= 500 /(60 45)= 500/105 = 4.76 ...
roundUp(totalTime)= 5

总运行时间= 5 *运行时间= 5 * 60 = 300

->要计算马走过的距离：

x =速度* totalRunTime = 14 * 300 = 4200

我将其翻译为以下代码：

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public class Kata {

public static int travel(int totalTime, int runTime, int restTime, int speed) {
int totalRunTime = 0;

if(totalTime < runTime){
totalRunTime = totalTime;
}else{
totalRunTime = (int)Math.ceil( (double)totalTime/(runTime + restTime) ) * runTime;
}

return speed * totalRunTime;
}
}

运行基本测试时，它会提供预期的输出：

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import org.junit.Test;
import static org.junit.Assert.assertEquals;
import org.junit.runners.JUnit4;

public class KataTest {

@Test
public void exampleTests() {
assertEquals(4200, Kata.travel(500, 60, 45, 14));
assertEquals(1120, Kata.travel(1000, 10, 127, 14));
assertEquals(1000, Kata.travel(100, 10, 0, 10));
assertEquals(1000, Kata.travel(100, 10, 0, 10));
assertEquals(450, Kata.travel(25, 50, 120, 18));
}
}

但是，当我们使用数字更大的高级示例进行测试时，它显示的结果不准确。

例如：

给出：速度= 6，运行时间= 34，rest时间= 180，总时间= 99094;预期的输出为94524，但是我发布的代码为我们提供了94656

我手动编写了跟踪以了解我的代码的作用：

->要计算这匹马奔跑的总时间：

totalTime /(runTime restTime)= 99094 /(34180)= 99094/214 = 463.05 ...
roundUp(totalTime)= 464

总运行时间= 464 *运行时间= 464 * 34 = 15776

->要计算马走了多远：

x =速度* totalRunTime = 6 * 15776 = 94656

因此失败的测试是：

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import org.junit.Test;
import static org.junit.Assert.assertEquals;
import org.junit.runners.JUnit4;

public class KataTest {

@Test
public void biggerTests() {
assertEquals(84954920, Kata.travel(35869784, 90, 100, 5));
}
}

我的直觉是必须在从double到int的转换或使用Math.ceil进行四舍五入的过程中改进代码，但是我不知道为什么或如何解决它。这是我认为我们可以改进的内容：

1	totalRunTime = (int)Math.ceil( (double)totalTime/(runTime + restTime) ) * runTime;

我也读过：

计算行驶距离
AnyLogic：如何计算行人的行进距离？
计算行进距离(而不是两者之间的距离)
如何计算旅行的总距离？
https://www.tutorialspoint.com/java/lang/math_ceil.htm