chall_1.go

package main

import "fmt"
import "bufio"
import "sort"
import "os"
import "strings"
import "strconv"

func convert_str(inp string) []int {
	var output []int

	var curr int
	curr = 1

	for _, elem := range(inp) {
		if elem == 'C' {
			curr = curr * 2
		} else {
			output = append(output, curr)
		}
	}

	return output
}

func calc(N int, inp string) int {
	var result int

	var str []int
	str = convert_str(inp)

	// temporary integer
	var tmp int

	// sum to keep track of
	var sum int

	if len(str) > N {
		result = -1
	} else {

		// get current total
		for i := 0; i < len(str); i++ {
			sum = sum + str[i]
		}

		for sum > N {

			// 'decrement' last boi and sum
			tmp = str[len(str)-1] / 2
			sum = sum - str[len(str)-1]/2

			// resort :/
			str[len(str)-1] = tmp
			sort.Ints(str)

			result = result + 1

		}

	}

	return result
}

func main() {

	reader := bufio.NewReader(os.Stdin)

	var T int
	fmt.Scanf("%d", &T)

	for i := 0; i < T; i++ {

		line, _, _ := reader.ReadLine()
		s := strings.Split(string(line), " ")

		N, _ := strconv.Atoi(s[0])
		inp := s[1]

		tmp := calc(N, inp)

		fmt.Print("Case #", i+1)
		fmt.Print(": ")
		if tmp == -1 {
			fmt.Println("IMPOSSIBLE")
		} else {
			fmt.Println(tmp)
		}
	}

}