code refactor

slice/sub.go

@@ -0,0 +1,54 @@
+package slice
+
+// Sub: a-b=?
+func SubInt64(a, b []int64) []int64 {
+	blen := len(b)
+	if blen == 0 {
+		return a
+	}
+
+	alen := len(a)
+	if alen == 0 {
+		return a
+	}
+
+	bset := make(map[int64]struct{}, blen)
+	for i := 0; i < blen; i++ {
+		bset[b[i]] = struct{}{}
+	}
+
+	ret := make([]int64, 0, alen)
+	for i := 0; i < alen; i++ {
+		if _, has := bset[a[i]]; !has {
+			ret = append(ret, a[i])
+		}
+	}
+
+	return ret
+}
+
+func SubString(a, b []string) []string {
+	blen := len(b)
+	if blen == 0 {
+		return a
+	}
+
+	alen := len(a)
+	if alen == 0 {
+		return a
+	}
+
+	bset := make(map[string]struct{}, blen)
+	for i := 0; i < blen; i++ {
+		bset[b[i]] = struct{}{}
+	}
+
+	ret := make([]string, 0, alen)
+	for i := 0; i < alen; i++ {
+		if _, has := bset[a[i]]; !has {
+			ret = append(ret, a[i])
+		}
+	}
+
+	return ret
+}