First version of the solver.

Reads the valid words, creates a histogram for letters and ranks words.

main.go

@@ -0,0 +1,110 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+	"sort"
+	"strings"
+)
+
+var letters = []string{"a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z"}
+var validWords = []string{}
+var dictionary = map[string]int{}
+var histogram = map[string]int{}
+var rankedWords PairList
+
+func main() {
+	// Read the valid words
+	fmt.Println("Reading words...")
+	err := readValidWords()
+	check(err)
+
+	// Generate histogram
+	fmt.Println("Building histogram...")
+	buildHistogram()
+
+	// Rank words based on frequency
+	fmt.Println("Ranking words...")
+	rankWords()
+
+	fmt.Printf("%+v\n", histogram)
+	for i := 0; i < 10; i++ {
+		rank := rankedWords[i]
+		fmt.Printf("%s: %d\n", rank.Key, rank.Value)
+	}
+}
+
+func check(e error) {
+	if e != nil {
+		panic(e)
+	}
+}
+
+func readValidWords() error {
+	file, err := os.Open("./solutions.txt")
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+
+	scanner := bufio.NewScanner(file)
+	i := 0
+	for scanner.Scan() {
+		word := scanner.Text()
+		dictionary[word] = i
+		validWords = append(validWords, word)
+		i++
+	}
+
+	if err := scanner.Err(); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func buildHistogram() {
+	histogram = make(map[string]int, len(letters))
+	for _, l := range letters {
+		histogram[l] = 0
+	}
+
+	// Loop through each word and check which unique letters are in the word
+	for _, word := range validWords {
+		chrs := strings.Split(word, "")
+
+		// Loop through each char and update the histogram
+		checkedChars := map[string]bool{}
+		for _, chr := range chrs {
+			// If we've not already processed this letter
+			if _, ok := checkedChars[chr]; !ok {
+				histogram[chr]++
+				checkedChars[chr] = true
+			}
+		}
+	}
+}
+
+func rankWords() {
+	rankedWords = make(PairList, len(validWords))
+
+	for _, word := range validWords {
+		chrs := strings.Split(word, "")
+		// First set the score based on the letters that exist
+		checkedChars := map[string]bool{}
+		score := 0
+		for _, chr := range chrs {
+			if _, ok := checkedChars[chr]; !ok {
+				score += histogram[chr]
+				checkedChars[chr] = true
+			}
+		}
+
+		// Add to the ranked list
+		rankedWords = append(rankedWords, Pair{word, score})
+	}
+
+	// Sort the
+	sort.Sort(sort.Reverse(rankedWords))
+}

pair.go

@@ -0,0 +1,12 @@
+package main
+
+type Pair struct {
+	Key   string
+	Value int
+}
+
+type PairList []Pair
+
+func (p PairList) Len() int           { return len(p) }
+func (p PairList) Swap(i, j int)      { p[i], p[j] = p[j], p[i] }
+func (p PairList) Less(i, j int) bool { return p[i].Value < p[j].Value }