Problem A. Magic Trick https://code.google.com/codejam/contest/2974486/dashboard#s=p0

magic_trick.go

package main

import (
        "bufio"
        "fmt"
        "log"
        "os"
        "strconv"
        "strings"
)

func usage() {
        if len(os.Args) <= 1 {
                fmt.Fprintf(os.Stderr, "usage: %s [inputfile]\n", os.Args[0])
                os.Exit(2)
        }
}

func parseInt(s string) int {
        i, _ := strconv.ParseInt(s, 10, 0)
        return int(i)
}

func parseCards(scanner *bufio.Scanner) (cards [4][4]int) {
        for i := 0; i < 4; i++ {
                scanner.Scan()
                line := scanner.Text()
                for j, v := range strings.Split(line, " ") {
                        cards[i][j] = parseInt(v)
                }
        }
        return cards
}

func main() {
        usage()

        file, err := os.Open(os.Args[1])
        if err != nil {
                log.Fatal(err)
        }
        defer file.Close()

        scanner := bufio.NewScanner(file)

        scanner.Scan()
        number_of_tests := parseInt(scanner.Text())
        //fmt.Println("Test: ", scanner.Text())

        for test_id := 1; test_id <= int(number_of_tests); test_id++ {
                scanner.Scan()
                chosen1 := parseInt(scanner.Text())
                cards1 := parseCards(scanner)

                scanner.Scan()
                chosen2 := parseInt(scanner.Text())
                cards2 := parseCards(scanner)

                //fmt.Printf("chosen %d: %d\n", test_id, chosen1)
                //fmt.Println(cards1)
                //fmt.Printf("chosen %d: %d\n", test_id, chosen2)
                //fmt.Println(cards2)

                matches, matched := findMatches(cards1, cards2, chosen1, chosen2)
                output(test_id, matches, matched)
        }
}

func findMatches(cards1, cards2 [4][4]int, chosen1, chosen2 int) (matches, matched int) {
        for _, v1 := range cards1[chosen1-1] {
                for _, v2 := range cards2[chosen2-1] {
                        if v1 == v2 {
                                matches += 1
                                matched = v1
                        }
                }
        }

        return matches, matched
}

func output(case_id, matches, matched int) {
        var answer string

        switch matches {
        case 0:
                answer = "Volunteer cheated!"
        case 1:
                answer = strconv.Itoa(matched)
        case 2, 3, 4:
                answer = "Bad magician!"
        }

        fmt.Printf("Case #%d: %s\n", case_id, answer)
}