Add solution for Challenge 6 by yz4230

Author: yz4230

challenge-6/submissions/yz4230/solution-template.go

@@ -0,0 +1,37 @@
+// Package challenge6 contains the solution for Challenge 6.
+package challenge6
+
+import "strings"
+
+func isSpace(c rune) bool {
+	return c == ' ' || c == '\t' || c == '\n' || c == '-'
+}
+
+func isLetter(c rune) bool {
+	return ('0' <= c && c <= '9') || ('a' <= c && c <= 'z') || ('A' <= c && c <= 'Z')
+}
+
+func CountWordFrequency(text string) map[string]int {
+	// Your implementation here
+	m := make(map[string]int)
+	parts := make([]string, 0)
+
+	buf := ""
+	for _, c := range text {
+		if len(buf) > 0 && isSpace(c) {
+			parts = append(parts, buf)
+			buf = ""
+		} else if isLetter(c) {
+			buf += string(c)
+		}
+	}
+	if len(buf) > 0 {
+		parts = append(parts, buf)
+	}
+
+	for _, part := range parts {
+		m[strings.ToLower(part)]++
+	}
+
+	return m
+}