refactor

2 files changed, 37 insertions, 4 deletions

diff --git a/ds/arraylist.go b/ds/arraylist.go
new file mode 100644
index 0000000..65c42ef
--- /dev/null
+++ b/ds/arraylist.go
@@ -0,0 +1,37 @@
+package ds
+
+import (
+	"fmt"
+	"strings"
+)
+
+type ArrayList []Comparer
+
+func (a ArrayList) FirstN(n int) string {
+	var sb strings.Builder
+	j := n
+
+	length := len(a)
+	if j > length {
+		j = length
+	}
+
+	for i := 0; i < j; i++ {
+		fmt.Fprintf(&sb, "%v ", a[i])
+	}
+
+	if j < length {
+		fmt.Fprintf(&sb, "... ")
+	}
+
+	return sb.String()
+}
+
+func (a ArrayList) Sorted() bool {
+	for i := len(a) - 1; i > 0; i-- {
+		if a[i].Lower(a[i-1]) {
+			return false
+		}
+	}
+	return true
+}
diff --git a/ds/comparer.go b/ds/comparer.go
index c132ea9..8fb3727 100644
--- a/ds/comparer.go
+++ b/ds/comparer.go
@@ -8,7 +8,3 @@ type Comparer interface {
 	HigherEqual(a Comparer) bool
 	Int() int
 }
-
-func (c []Comparer) firstN(n int) []Comparer {
-	return c
-}