GCJ/2008/Qualification/A/main.go

package main

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

func readInt(s *bufio.Scanner) int {
	s.Scan()
	i, _ := strconv.ParseInt(s.Text(), 10, 32)
	return int(i)
}

func readStr(s *bufio.Scanner) string {
	s.Scan()
	return s.Text()
}

func leastSwitch(scanner *bufio.Scanner) []int {
	caseCnt := readInt(scanner)
	answer := make([]int, caseCnt)
	for i := 0; i < caseCnt; i++ {
		engineCnt := readInt(scanner)
		for j := 0; j < engineCnt; j++ {
			readStr(scanner)
		}
		queryCnt := readInt(scanner)
		if queryCnt == 0 {
			answer = append(answer, 0)
			continue // Go to next case
		}
		querySet := make(map[string]bool) // A set stores current queries
		for j := 0; j < queryCnt; j++ {
			engine := readStr(scanner)
			if _, ok := querySet[engine]; !ok {
				if len(querySet) == engineCnt-1 {
					querySet = make(map[string]bool)
					answer[i]++
				}
				querySet[engine] = true
			}
		}
	}
	return answer
}

func main() {
	inputFiles := []string{"A-small-practice.in", "A-large-practice.in", "test.in"}
	outputFiles := []string{"result-small.out", "result-large.out", "test.out"}
	const (
		small = iota
		large
		test
	)

	fileType := large

	fin, _ := os.Open(inputFiles[fileType])
	defer fin.Close()

	scanner := bufio.NewScanner(fin)
	answer := leastSwitch(scanner)

	fout, _ := os.Create(outputFiles[fileType])
	defer fout.Close()

	for i, n := range answer {
		s := fmt.Sprintf("Case #%d: %d\n", i+1, n)
		fout.WriteString(s)
	}
}