https://www.fogcreek.com/Jobs/SupportEngineer/

fog.go

package main

import (
	"fmt"
	"io/ioutil"
	"sort"
	"strings"
)

func main() {
	letters := "abcdefghijklmnopqrstuvwxyz_"

	text, err := ioutil.ReadFile("text.txt")
	if err != nil {
		fmt.Println("ReadFile error: ", err.Error())
	}

	splitedList := strings.Split(letters, "")
	countOfElements := make(map[int]string)
	for _, v := range splitedList {
		countOfElements[strings.Count(string(text), v)] = v
	}

	// This order trick was shamelessly copied from Andrew Gerrand
	// Here http://blog.golang.org/go-maps-in-action
	var keys []int
	for k := range countOfElements {
		keys = append(keys, k)
	}
	// Source: https://golang.org/pkg/sort/#Reverse
	sort.Sort(sort.Reverse(sort.IntSlice(keys)))

	var secret []string
	for _, k := range keys {
		secret = append(secret, countOfElements[k])
	}

	secretWord := strings.Split(strings.Join(secret, ""), "_")[0]
	fmt.Println(secretWord)
}