[Arrays & Hashing][Encode and Decode Strings] - Implement solution for Leetcode 271

1_arrays_and_hashing/6_encode_and_decode_strings/solution.go

@@ -0,0 +1,40 @@
+package encodeanddecodestrings
+
+import (
+	"strconv"
+	"strings"
+)
+
+// Time complexity: O(n), where n is the total length of all strings in the input slice.
+// Space complexity: O(n)
+func Encode(strs []string) string {
+	var sb strings.Builder
+	for _, str := range strs {
+		sb.WriteString(strconv.Itoa(len(str)))
+		sb.WriteString("#")
+		sb.WriteString(str)
+	}
+	return sb.String()
+}
+
+// Time complexity: O(n), where n is the total length of the encoded string.
+// Space complexity: O(n)
+func Decode(s string) []string {
+	if len(s) == 0 {
+		return []string{}
+	}
+	var result []string
+	i := 0
+	for i < len(s) {
+		j := i
+		for s[j] != '#' {
+			j++
+		}
+		length, _ := strconv.Atoi(s[i:j])
+		j++
+		str := s[j : j+length]
+		result = append(result, str)
+		i = j + length
+	}
+	return result
+}

1_arrays_and_hashing/6_encode_and_decode_strings/solution_test.go

@@ -0,0 +1,32 @@
+package encodeanddecodestrings
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestEncodeDecode(t *testing.T) {
+	cases := []struct {
+		name     string
+		input    []string
+		expected []string
+	}{
+		{"Basic strings", []string{"hello", "world"}, []string{"hello", "world"}},
+		{"Empty strings", []string{"", "", ""}, []string{"", "", ""}},
+		{"Strings with special characters", []string{"a#b", "c$d", "e^f"}, []string{"a#b", "c$d", "e^f"}},
+		{"Mixed lengths", []string{"short", "", "a", "longerstring"}, []string{"short", "", "a", "longerstring"}},
+		{"Single string", []string{"onlyone"}, []string{"onlyone"}},
+		{"Empty list", []string{}, []string{}},
+	}
+
+	for _, c := range cases {
+		t.Run(c.name, func(t *testing.T) {
+			encoded := Encode(c.input)
+			decoded := Decode(encoded)
+
+			if !reflect.DeepEqual(decoded, c.expected) {
+				t.Errorf("Decode(Encode(%v)) = %v; want %v", c.input, decoded, c.expected)
+			}
+		})
+	}
+}