judge.go

gistfile1.go

package main

import (
	"fmt"
	"os"
	"os/exec"
	"strings"
	"time"
	"bufio"
)

const (
	timeout = 20 * time.Second
)

type error interface {
	Error() string
}

func nameParts(filename string) (string, string) {
	parts := strings.Split(filename, ".")
	if len(parts) != 2 {
		return "", ""
	}
	return parts[0], parts[1]
}

// Takes a filename scanned in from the
//     main function and returns a command
//     that is waiting to be started and read
//     input from
func build(filename string) error {
	command := exec.Command("javac", filename)
	error := command.Run()
	return error
}

// Runs the file
func getCommand(filename string) *exec.Cmd {
	name, _ := nameParts(filename)
	command := exec.Command("java", name)
	return command
}

func main() {
	var filename string
	fmt.Scanln(&filename)

	if err := build(filename); err != nil {
		fmt.Println("Failed to compile")
		fmt.Println(err)
		return
	}

	cmd := getCommand(filename)

	output, err := os.Create("./out.txt")
	if err != nil {
		fmt.Println(err)
		return
	}
	errorOut, err := os.Create("./err.txt")
	if err != nil {
		fmt.Println(err)
		return
	}
	input, err := os.Open("./in.txt")
	if err != nil {
		fmt.Println(err)
		return
	}
	cmd.Stdin = input
	cmd.Stderr = errorOut
	cmd.Stdout = output

	procErr := make(chan error)
	go func() {
		procErr <- cmd.Run()
	}()

	endTime := time.Now().Add(timeout)
	completed := false
	err = nil
	for time.Now().Before(endTime) && !completed {
		select {
		default:
			time.Sleep(time.Second)
		case err = <-procErr:
			completed = true
		}
	}
	if !completed {
		cmd.Process.Kill()
		fmt.Println("Took too long")
		return
	}
	if err != nil {
		fmt.Println("Runtime error")
		return
	}
	input.Close()
	errorOut.Close()
	output.Close()

	correct, err := os.Open("./correct.txt")
	if err != nil {
		fmt.Println(err)
		return
	}
	
	output, err = os.Open("./out.txt")
	if err != nil {
		fmt.Println(err)
		return
	}

	equal := true
	f1scanner := bufio.NewScanner(correct)
	f2scanner := bufio.NewScanner(output)
	f1scanner.Split(bufio.ScanLines)
	f2scanner.Split(bufio.ScanLines)
	f1 := f1scanner.Scan()
	f2 := f2scanner.Scan()
	for f1 && f2 {
		if (f1scanner.Text() != f2scanner.Text()) {
			equal = false
			break
		}
		f1 = f1scanner.Scan()
		f2 = f2scanner.Scan()
	}
	if equal && f1 == f2 {
		fmt.Println("Correct solution!")
	} else {
		fmt.Println("Incorrect solution")
	}
}