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https://github.com/randomtask2000/ballclock


https://github.com/randomtask2000/ballclock

ball-clocks ballclock hour-indicator java minutes-track

Last synced: 11 months ago
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README 

          
## Ball Clock Assignment

Movement has long been used to measure time. For example, the ball clock is a simple device

which keeps track of the passing minutes by moving ball-bearings. Each minute, a rotating arm

removes a ball bearing from the queue at the bottom, raises it to the top of the clock and

deposits it on a track leading to indicators displaying minutes, five-minutes, and hours. These

indicators display the time between `1:00` and `12:59`, but without 'a.m.' or 'p.m.' indicators.

Thus 2 balls in the minute indicator, 6 balls in the five-minute indicator and 5 balls in the hour

indicator displays the time `5:32`.



Unfortunately, most commercially available ball clocks do not incorporate a date indication,

although this would be simple to do with the addition of further carry and indicator tracks.

However, all is not lost! As the balls migrate through the mechanism of the clock, the order

they are found in can be used to determine the time elapsed since the clock had some specific

ordering. The length of time which can be measured is limited because the orderings of the

balls eventually begin to repeat. Your program must compute the time before repetition, which

varies according to the total number of balls present.



#### Operation of the Ball Clock

Every minute, the least recently used ball is removed from the queue of balls at the bottom of

the clock, elevated, then deposited on the minute indicator track, which is able to hold four

balls. When a fifth ball rolls on to the minute indicator track, its weight causes the track to tilt.

The four balls already on the track run back down to join the queue of balls waiting at the

bottom in reverse order of their original addition to the minutes track. The fifth ball, which

caused the tilt, rolls down to the five-minute indicator track. This track holds eleven balls. The

twelfth ball carried over from the minutes causes the five-minute track to tilt, returning the

eleven balls to the queue, again in reverse order of their addition. The twelfth ball rolls down

to the hour indicator. The hour indicator also holds eleven balls, but has one extra fixed ball

which is always present so that counting the balls in the hour indicator will yield an hour in the

range one to twelve. The twelfth ball carried over from the five-minute indicator causes the

hour indicator to tilt, returning the eleven free balls to the queue, in reverse order, before the

twelfth ball itself also returns to the queue.



#### Guidelines

The exercise may be completed in `Java`, `Go`, `Python`, or `JavaScript`. You are welcome to do it in

more than one of the languages.

Note: If you are doing this assignment as part of an application for employment, check with

your recruiter to determine what language(s) to use.

No permutation or `LCM` algorithms are allowed. A full simulation is required. Please ensure

that your code moves each ball.



#### Implementation

Valid numbers of balls are in the range `27` to `127`. Ball inputs outside of this range should

produce an error message. Clocks must support two modes of computation. Each mode is

described below, along with sample inputs and outputs. For each mode, a final line of output

should indicate the amount of time (in both milliseconds and seconds) it took for the clock to

complete that run.



#### Mode 1 (Cycle Days)

The first mode takes a single parameter specifying the number of balls and reports the number

of balls given in the input and the number of days (24-hour periods) which elapse before the

clock returns to its initial ordering.



An input of 30 yields the following output:

```

30 balls cycle after 15 days.

Completed in x milliseconds (y.yyy seconds)

```

An input of 45 yields the following output:

```

45 balls cycle after 378 days.

Completed in x milliseconds (y.yyy seconds)

```



#### Mode 2 (Clock State)

The second mode takes two parameters, the number of balls and the number of minutes to run

for. If the number of minutes is specified, the clock must run to the number of minutes and

report the state of the tracks at that point in a `JSON` format.

An input of `30` `325` yields the following output:

```json

{"Min":[],"FiveMin":[22,13,25,3,7],"Hour":[6,12,17,4,15],"Main":

[11,5,26,18,2,30,19,8,24,10,29,20,16,21,28,1,23,14,27,9]}

```

#### Run with Gradle

```bash

./gradlew clean build

```

Run with no input arguments:

```bash

java -jar build/libs/BallClock-1.0.jar

```

The application will the below message prompting you to pass an argument

```

No args were passed! 

Please enter the following args

 -b (-balls, -balls) 27                 : number of balls needs to be between

                                          27 to 127

 -h (-help)                             : display options (default: false)

 -t (-minutes, -time, -m, -timeToRun) 1 : number of minutes needs to

                                          be greater than zero

 -v (-verbose)                          : display message (default: false)

```

Or run the application directly through `gradle`

```bash

gradle run 

> Task :run 

{"Minutes":[],"FiveMin":[22,13,25,3,7],"Hours":[6,12,17,4,15],"Main":[11,5,26,18,2,30,19,8,24,10,29,20,16,21,28,1,23,14,27,9]}

```

An input of `-balls 27` yields the following output:

```bash

java -jar build/libs/BallClock-1.0.jar -balls 27

27 balls cycle after 23 days.

Completed in 13 milliseconds (0.013 seconds)

```

An input of `-balls 30` `-minutes 325` yields the following output:

```bash

java -jar build/libs/BallClock-1.0.jar -balls 30 -minutes 325

```

Output:

```json

{"Minutes":[],"FiveMin":[22,13,25,3,7],"Hours":[6,12,17,4,15],"Main":[11,5,26,18,2,30,19,8,24,10,29,20,16,21,28,1,23,14,27,9]}

```