moraes · September 28, 2025 09:56 · Jan 13, 2013 · Jan 13, 2013 · Jan 13, 2013 · Jan 13, 2013
diff --git a/gistfile1.go b/gistfile1.go
@@ -34,9 +34,8 @@ func (s *Stack) Pop() *Node {
 	if s.count == 0 {
 		return nil
 	}
-	node := s.nodes[s.count-1]
 	s.count--
-	return node
+	return s.nodes[s.count]
 }
 
 // NewQueue returns a new queue with the given initial size.

diff --git a/gistfile1.go b/gistfile1.go
@@ -12,29 +12,20 @@ func (n *Node) String() string {
 	return fmt.Sprint(n.Value)
 }
 
-// NewStack returns a stack with the given initial size.
-func NewStack(size int) *Stack {
-	return &Stack{
-		nodes: make([]*Node, size),
-		size:  size,
-	}
+// NewStack returns a new stack.
+func NewStack() *Stack {
+	return &Stack{}
 }
 
 // Stack is a basic LIFO stack that resizes as needed.
 type Stack struct {
 	nodes []*Node
-	size  int
 	count int
 }
 
 // Push adds a node to the stack.
 func (s *Stack) Push(n *Node) {
-	if s.count >= len(s.nodes) {
-		nodes := make([]*Node, len(s.nodes)+s.size)
-		copy(nodes, s.nodes)
-		s.nodes = nodes
-	}
-	s.nodes[s.count] = n
+	s.nodes = append(s.nodes[:s.count], n)
 	s.count++
 }
 
@@ -48,7 +39,7 @@ func (s *Stack) Pop() *Node {
 	return node
 }
 
-// NewQueue returns a queue with the given initial size.
+// NewQueue returns a new queue with the given initial size.
 func NewQueue(size int) *Queue {
 	return &Queue{
 		nodes: make([]*Node, size),
@@ -92,7 +83,7 @@ func (q *Queue) Pop() *Node {
 }
 
 func main() {
-	s := NewStack(1)
+	s := NewStack()
 	s.Push(&Node{1})
 	s.Push(&Node{2})
 	s.Push(&Node{3})

diff --git a/gistfile1.go b/gistfile1.go
@@ -15,7 +15,7 @@ func (n *Node) String() string {
 // NewStack returns a stack with the given initial size.
 func NewStack(size int) *Stack {
 	return &Stack{
-		nodes: make([]*Node, 3),
+		nodes: make([]*Node, size),
 		size:  size,
 	}
 }
@@ -51,7 +51,7 @@ func (s *Stack) Pop() *Node {
 // NewQueue returns a queue with the given initial size.
 func NewQueue(size int) *Queue {
 	return &Queue{
-		nodes: make([]*Node, 3),
+		nodes: make([]*Node, size),
 		size:  size,
 	}
 }

diff --git a/gistfile1.go b/gistfile1.go
@@ -30,7 +30,7 @@ type Stack struct {
 // Push adds a node to the stack.
 func (s *Stack) Push(n *Node) {
 	if s.count >= len(s.nodes) {
-		nodes := make([]*Node, len(s.nodes)*2)
+		nodes := make([]*Node, len(s.nodes)+s.size)
 		copy(nodes, s.nodes)
 		s.nodes = nodes
 	}
@@ -68,7 +68,7 @@ type Queue struct {
 // Push adds a node to the queue.
 func (q *Queue) Push(n *Node) {
 	if q.head == q.tail && q.count > 0 {
-		nodes := make([]*Node, len(q.nodes)*2)
+		nodes := make([]*Node, len(q.nodes)+q.size)
 		copy(nodes, q.nodes[q.head:])
 		copy(nodes[len(q.nodes)-q.head:], q.nodes[:q.head])
 		q.head = 0

diff --git a/gistfile1.go b/gistfile1.go
@@ -8,9 +8,22 @@ type Node struct {
 	Value int
 }
 
+func (n *Node) String() string {
+	return fmt.Sprint(n.Value)
+}
+
+// NewStack returns a stack with the given initial size.
+func NewStack(size int) *Stack {
+	return &Stack{
+		nodes: make([]*Node, 3),
+		size:  size,
+	}
+}
+
 // Stack is a basic LIFO stack that resizes as needed.
 type Stack struct {
 	nodes []*Node
+	size  int
 	count int
 }
 
@@ -35,9 +48,18 @@ func (s *Stack) Pop() *Node {
 	return node
 }
 
+// NewQueue returns a queue with the given initial size.
+func NewQueue(size int) *Queue {
+	return &Queue{
+		nodes: make([]*Node, 3),
+		size:  size,
+	}
+}
+
 // Queue is a basic FIFO queue based on a circular list that resizes as needed.
 type Queue struct {
 	nodes []*Node
+	size  int
 	head  int
 	tail  int
 	count int
@@ -70,15 +92,15 @@ func (q *Queue) Pop() *Node {
 }
 
 func main() {
-	s := &Stack{nodes: make([]*Node, 3)}
+	s := NewStack(1)
 	s.Push(&Node{1})
 	s.Push(&Node{2})
 	s.Push(&Node{3})
-	fmt.Printf("%v, %v, %v\n", s.Pop().Value, s.Pop().Value, s.Pop().Value)
-	
-	q := &Queue{nodes: make([]*Node, 3)}
-	q.Push(&Node{1})
-	q.Push(&Node{2})
-	q.Push(&Node{3})
-	fmt.Printf("%v, %v, %v\n", q.Pop().Value, q.Pop().Value, q.Pop().Value)
+	fmt.Println(s.Pop(), s.Pop(), s.Pop())
+
+	q := NewQueue(1)
+	q.Push(&Node{4})
+	q.Push(&Node{5})
+	q.Push(&Node{6})
+	fmt.Println(q.Pop(), q.Pop(), q.Pop())
 }
diff --git a/gistfile1.go b/gistfile1.go
@@ -8,7 +8,7 @@ type Node struct {
 	Value int
 }
 
-// A basic LIFO stack.
+// Stack is a basic LIFO stack that resizes as needed.
 type Stack struct {
 	nodes []*Node
 	count int
@@ -35,7 +35,7 @@ func (s *Stack) Pop() *Node {
 	return node
 }
 
-// A basic FIFO queue based on a circular list.
+// Queue is a basic FIFO queue based on a circular list that resizes as needed.
 type Queue struct {
 	nodes []*Node
 	head  int

diff --git a/gistfile1.go b/gistfile1.go
@@ -0,0 +1,84 @@
+package main
+
+import (
+	"fmt"
+)
+
+type Node struct {
+	Value int
+}
+
+// A basic LIFO stack.
+type Stack struct {
+	nodes []*Node
+	count int
+}
+
+// Push adds a node to the stack.
+func (s *Stack) Push(n *Node) {
+	if s.count >= len(s.nodes) {
+		nodes := make([]*Node, len(s.nodes)*2)
+		copy(nodes, s.nodes)
+		s.nodes = nodes
+	}
+	s.nodes[s.count] = n
+	s.count++
+}
+
+// Pop removes and returns a node from the stack in last to first order.
+func (s *Stack) Pop() *Node {
+	if s.count == 0 {
+		return nil
+	}
+	node := s.nodes[s.count-1]
+	s.count--
+	return node
+}
+
+// A basic FIFO queue based on a circular list.
+type Queue struct {
+	nodes []*Node
+	head  int
+	tail  int
+	count int
+}
+
+// Push adds a node to the queue.
+func (q *Queue) Push(n *Node) {
+	if q.head == q.tail && q.count > 0 {
+		nodes := make([]*Node, len(q.nodes)*2)
+		copy(nodes, q.nodes[q.head:])
+		copy(nodes[len(q.nodes)-q.head:], q.nodes[:q.head])
+		q.head = 0
+		q.tail = len(q.nodes)
+		q.nodes = nodes
+	}
+	q.nodes[q.tail] = n
+	q.tail = (q.tail + 1) % len(q.nodes)
+	q.count++
+}
+
+// Pop removes and returns a node from the queue in first to last order.
+func (q *Queue) Pop() *Node {
+	if q.count == 0 {
+		return nil
+	}
+	node := q.nodes[q.head]
+	q.head = (q.head + 1) % len(q.nodes)
+	q.count--
+	return node
+}
+
+func main() {
+	s := &Stack{nodes: make([]*Node, 3)}
+	s.Push(&Node{1})
+	s.Push(&Node{2})
+	s.Push(&Node{3})
+	fmt.Printf("%v, %v, %v\n", s.Pop().Value, s.Pop().Value, s.Pop().Value)
+
+	q := &Queue{nodes: make([]*Node, 3)}
+	q.Push(&Node{1})
+	q.Push(&Node{2})
+	q.Push(&Node{3})
+	fmt.Printf("%v, %v, %v\n", q.Pop().Value, q.Pop().Value, q.Pop().Value)
+}