From 98ef0e8da99dc5704f6a33070fd1671b271cf048 Mon Sep 17 00:00:00 2001
From: Andrew Gillis <gillis.andrewj@gmail.com>
Date: Wed, 3 Aug 2016 13:27:42 -0400
Subject: [PATCH 1/2] Get() accepts negative index.

---
 queue.go      |  8 +++++++-
 queue_test.go | 15 ++++++++++++++-
 2 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/queue.go b/queue.go
index 2dc8d93..6fe6ca8 100644
--- a/queue.go
+++ b/queue.go
@@ -65,8 +65,14 @@ func (q *Queue) Peek() interface{} {
 }
 
 // Get returns the element at index i in the queue. If the index is
-// invalid, the call will panic.
+// invalid, the call will panic. This method accepts both positive and
+// negative index values. Index 0 refers to the first element, and
+// index -1 refers to the last.
 func (q *Queue) Get(i int) interface{} {
+	// If indexing backwards, convert to positive index.
+	if i < 0 {
+		i = q.count + i
+	}
 	if i < 0 || i >= q.count {
 		panic("queue: Get() called with index out of range")
 	}
diff --git a/queue_test.go b/queue_test.go
index f2765c1..213c3c7 100644
--- a/queue_test.go
+++ b/queue_test.go
@@ -69,6 +69,19 @@ func TestQueueGet(t *testing.T) {
 	}
 }
 
+func TestQueueGetNegative(t *testing.T) {
+	q := New()
+
+	for i := 0; i < 1000; i++ {
+		q.Add(i)
+		for j := 1; j <= q.Length(); j++ {
+			if q.Get(-j).(int) != q.Length()-j {
+				t.Errorf("index %d doesn't contain %d", -j, q.Length()-j)
+			}
+		}
+	}
+}
+
 func TestQueueGetOutOfRangePanics(t *testing.T) {
 	q := New()
 
@@ -77,7 +90,7 @@ func TestQueueGetOutOfRangePanics(t *testing.T) {
 	q.Add(3)
 
 	assertPanics(t, "should panic when negative index", func() {
-		q.Get(-1)
+		q.Get(-4)
 	})
 
 	assertPanics(t, "should panic when index greater than length", func() {

From 04e142afea9877976c7b0f9c9049fb2c58795498 Mon Sep 17 00:00:00 2001
From: Andrew Gillis <gillis.andrewj@gmail.com>
Date: Wed, 3 Aug 2016 14:07:53 -0400
Subject: [PATCH 2/2] += notation

---
 queue.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/queue.go b/queue.go
index 6fe6ca8..6b79323 100644
--- a/queue.go
+++ b/queue.go
@@ -71,7 +71,7 @@ func (q *Queue) Peek() interface{} {
 func (q *Queue) Get(i int) interface{} {
 	// If indexing backwards, convert to positive index.
 	if i < 0 {
-		i = q.count + i
+		i += q.count
 	}
 	if i < 0 || i >= q.count {
 		panic("queue: Get() called with index out of range")