GCJ/2008/1C/A/main.go

package main

import (
	"bufio"
	"fmt"
	"os"
	"sort"
)

// IntSlice ...
type IntSlice []int

func (a IntSlice) Len() int           { return len(a) }
func (a IntSlice) Less(i, j int) bool { return a[i] > a[j] }
func (a IntSlice) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }

func leastPress(scanner *bufio.Scanner) []int {
	caseCnt := ReadInt(scanner)
	answer := make([]int, caseCnt)
	for cid := 0; cid < caseCnt; cid++ {
		params := ReadInts(scanner)
		// P: maximum cnt to place; K: key cnt; L: alphabet letter cnt.
		P, K, L := params[0], params[1], params[2]
		var freq IntSlice = ReadInts(scanner)
		sort.Sort(freq)
		for p, i := 0, 0; p < P && i < L; p++ {
			for j := 0; j < K && i < L; i, j = i+1, j+1 {
				answer[cid] += (p + 1) * freq[i]
			}
		}
	}
	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 := test

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

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

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

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