LiftScheduler Visualization

To aid in the development of your submission, we are providing a visualization tool to competitors. The tool is packaged as an executable jar, which can be run either by double clicking it (in windows anyway) or from the command line as "java -Xmx256M -jar Tester.jar".

As in previous contests, to use this visualization tool, you should create an application that communicates with the tool via standard in and standard out. Note that this does not effect the way your program should work when you submit it on the TopCoder website. The program that you write for the visualizer should implement the following pseudocode:

    
nextInt() -- reads an integer from standard in, delimited by whitespace

nextString() -- reads a string from standard in, delimited by whitespace

nextIntArray()
    length = nextInt()
    for(i = 0; i<length; i++)
        ret[i] = nextInt()
    return ret

main()
    method = nextInt()
    while(method != -1)
        if(method == 0)
            N = nextInt()
            M = nextInt()
            C = nextInt()
            initialise(N,M,C)
        else if(method == 1)
            upRequests = nextIntArray()
            downRequests = nextIntArray()
            liftRequests = nextIntArray()
            destinationRequests = nextIntArray()
            state = nextString()
            println(step(upRequests,downRequests,liftRequests,destinationRequests,state))
            flush(stdout)
        method = nextInt()

Using the visualizer

To use the visualizer, you must have Java 1.5 or greater installed. To run the visualizer, you can execute the command "java -Xmx256M -jar Tester.jar". This will open up a new window containing the visualization, along with a number of controls. The first thing you will need to do is specify the executable you have made for your lift code. You may either enter its path, or select it via the button provided. If your executable requires arguments, enter them in the provided field. For example, if your executable is a Java class LiftScheduler.class, you should enter something like "java LiftScheduler" (without the quotes) in this field (replacing "java" with the full path to the Java executable if necessary). The exact details of what you enter here will depend on your language choice. In particular, in Java, you will need to make sure that the class file is in the same directory as Tester.jar, or else you will need to specify a classpath along with the executable location and class name.

You may customize the test case by entering any values for the parameters that you like. The field seed is a seed for the random number generator and will allow you to repeatedly generate the same test case. You can select new random values for all parameters by clicking "New Parameters". If you've changed the seed since you last generated parameters the new seed will be used to generate new parameters, otherwise a new seed will be generated along with new parameters. To test the examples from the problem statement, you may simply enter the appropriate seeds and click "New Parameters".

Once you've started the simulation, any output you write to standard error, along with messages from the visualization tool will appear in the visualization. You may control the speed with the slider on the top of the control panel.

Command Line Options

You can specify a number of parameters on the command line to simplify the automation of testing (though you don't need to use any of them). For example, "java -jar Tester.jar -seed 5" will set the seed to 5 when running the tool.

-N <N>
-M <M>
-C <C>
-P <P>
-businessprob <businessprob>
-seed <seed>	Specify the initial seed
-exec <command>	Specify the command to execute your code
-novis	Run the test case without the visualizer (requires -exec, implies -go)
-go	Start running immediately (requires -exec)
-onewindow	Run in one window instead of 3

Final Notes

The source is in the jar file. You can extract it at the command line by running "jar -xf Tester.jar".
Make sure you flush your buffers after writing to standard out, or the visualization tool might not get your output, and it will appear to hang.
Java users: if you get something java.lang.NoClassDefFoundError LiftScheduler, it means that you've correctly set the path to Java, but Java can't find your class. Among other things, you can try setting the command to something like "PATH1\java -cp PATH2 LiftScheduler", where PATH2 is the location of your class file.
If the simulation fails to go, but there are no error messages, the most likely explanation is that the visualization tool is still waiting for your program to tell it what to do next. An obvious cause for this is that your program is in some sort of an infinite loop. Another possible cause is that your program is waiting for input which it will never get, as the visualization tool is waiting for your program.
Please note that, while we will do our best to make the workings of the visualizer as clear as possible, it is impossible for us to help everyone debug their code to make it work with the visualization tool. If you do think you have discovered a bug, please email lbackstrom@topcoder.com or post the bug to the forums. The more details you provide, the more likely you are to be helped quickly. Please to NOT post code to the forums, as that is against the rules, and you will be disqualified.