[feature]: complete hw3

Author: kpechenenko

hw03_frequency_analysis/.sync

@@ -1,4 +1,4 @@
-module github.com/fixme_my_friend/hw03_frequency_analysis
+module github.com/kpechenenko/otus-go-hw/hw03_frequency_analysis
 
 go 1.19
 

hw03_frequency_analysis/go.mod

@@ -1,6 +1,38 @@
 package hw03frequencyanalysis
 
-func Top10(_ string) []string {
-	// Place your code here.
-	return nil
+import (
+	"sort"
+	"strings"
+)
+
+func Top10(s string) []string {
+	if len(s) == 0 {
+		return []string{}
+	}
+	words := strings.Fields(s)
+	if len(words) == 0 {
+		return []string{}
+	}
+	frequency := make(map[string]int)
+	for _, w := range words {
+		frequency[w]++
+	}
+	uniqueWords := make([]string, 0)
+	for w := range frequency {
+		uniqueWords = append(uniqueWords, w)
+	}
+	sort.Slice(
+		uniqueWords,
+		func(i, j int) bool {
+			diff := frequency[uniqueWords[i]] - frequency[uniqueWords[j]]
+			if diff == 0 {
+				return strings.Compare(uniqueWords[i], uniqueWords[j]) < 0
+			}
+			return diff > 0
+		})
+	topLimit := 10
+	if len(uniqueWords) <= topLimit {
+		return uniqueWords
+	}
+	return uniqueWords[:topLimit]
 }

hw03_frequency_analysis/top.go

@@ -80,3 +80,19 @@ func TestTop10(t *testing.T) {
 		}
 	})
 }
+
+func TestTop10_9Elems(t *testing.T) {
+	s := "a b b c c c d d d d e e e e e f f f f f f g g g g g g g"
+	expected := []string{"g", "f", "e", "d", "c", "b", "a"}
+	t.Run("9 letters in reverse alphabetic orders", func(t *testing.T) {
+		require.Equal(t, expected, Top10(s))
+	})
+}
+
+func TestTop10_Only1Elems(t *testing.T) {
+	s := "a"
+	expected := []string{"a"}
+	t.Run("only 1 letter", func(t *testing.T) {
+		require.Equal(t, expected, Top10(s))
+	})
+}