[Sync Iteration] go/custom-set/1

solutions/go/custom-set/1/custom_set.go

@@ -0,0 +1,140 @@
+package stringset
+
+import (
+	"fmt"
+	"slices"
+	"strings"
+)
+
+// Implement Set as a collection of unique string values.
+//
+// For Set.String, use '{' and '}', output elements as double-quoted strings
+// safely escaped with Go syntax, and use a comma and a single space between
+// elements. For example, a set with 2 elements, "a" and "b", should be formatted as {"a", "b"}.
+// Format the empty set as {}.
+
+// Define the Set type here.
+type Set struct {
+	s []string
+}
+
+func New() Set {
+	return Set{}
+}
+
+func removeDuplicateStr(strSlice []string) []string {
+	allKeys := make(map[string]struct{}, len(strSlice))
+	list := make([]string, 0, len(strSlice))
+	for _, item := range strSlice {
+		if _, exists := allKeys[item]; !exists {
+			allKeys[item] = struct{}{}
+			list = append(list, item)
+		}
+	}
+	return list
+}
+
+func NewFromSlice(l []string) Set {
+	return Set{removeDuplicateStr(l)}
+}
+
+func (s Set) String() string {
+	if len(s.s) == 0 {
+		return "{}"
+	}
+	return fmt.Sprintf(`{"%s"}`, strings.Join(s.s, "\", \""))
+}
+
+func (s Set) IsEmpty() bool {
+	return len(s.s) == 0
+}
+
+func (s Set) Has(elem string) bool {
+	return slices.Contains(s.s, elem)
+}
+
+func (s *Set) Add(elem string) {
+	if !s.Has(elem) {
+		s.s = append(s.s, elem)
+	}
+}
+
+func Subset(s1, s2 Set) bool {
+	m := make(map[string]struct{}, len(s2.s))
+	for _, s := range s2.s {
+		m[s] = struct{}{}
+	}
+
+	for _, s := range s1.s {
+		if _, found := m[s]; !found {
+			return false
+		}
+	}
+
+	return true
+}
+
+func Disjoint(s1, s2 Set) bool {
+	m := make(map[string]struct{}, len(s2.s))
+	for _, s := range s2.s {
+		m[s] = struct{}{}
+	}
+
+	for _, s := range s1.s {
+		if _, found := m[s]; found {
+			return false
+		}
+	}
+	return true
+}
+
+func Equal(s1, s2 Set) bool {
+	if len(s1.s) != len(s2.s) {
+		return false
+	}
+
+	m := make(map[string]struct{}, len(s2.s))
+	for _, s := range s2.s {
+		m[s] = struct{}{}
+	}
+
+	for _, s := range s1.s {
+		if _, found := m[s]; !found {
+			return false
+		}
+	}
+
+	return true
+}
+
+func Intersection(s1, s2 Set) (res Set) {
+	for _, s := range s1.s {
+		if s2.Has(s) {
+			res.Add(s)
+		}
+	}
+
+	return res
+}
+
+func Difference(s1, s2 Set) (res Set) {
+	for _, s := range s1.s {
+		if !s2.Has(s) {
+			res.Add(s)
+		}
+	}
+
+	return res
+}
+
+func Union(s1, s2 Set) (res Set) {
+	for _, s := range s1.s {
+		res.Add(s)
+	}
+
+	for _, s := range s2.s {
+		res.Add(s)
+	}
+
+	return res
+}