master > master: code - stacks + queues data structures überarbeitet

code/golang/pkg/data_structures/queues/queues.go

@@ -0,0 +1,81 @@
+package queues
+
+/* ---------------------------------------------------------------- *
+ * IMPORTS
+ * ---------------------------------------------------------------- */
+
+import (
+	"fmt"
+	"strings"
+)
+
+/* ---------------------------------------------------------------- *
+ * GLOBAL VARIABLES/CONSTANTS
+ * ---------------------------------------------------------------- */
+
+//
+
+/* ---------------------------------------------------------------- *
+ * TYPE
+ * ---------------------------------------------------------------- */
+
+type QueueInt struct {
+	values *[]int
+}
+
+/* ---------------------------------------------------------------- *
+ * METHODS stacks
+ * ---------------------------------------------------------------- */
+
+func CREATE() QueueInt {
+	return QueueInt{}
+}
+
+func (S *QueueInt) INIT() {
+	S.values = &[]int{}
+}
+
+func (S QueueInt) Length() int {
+	if S.values == nil {
+		return 0
+	}
+	return len(*S.values)
+}
+
+func (S QueueInt) String() string {
+	if S.EMPTY() {
+		return "-"
+	}
+	values := []string{}
+	n := S.Length()
+	for i := n - 1; i >= 0; i-- {
+		value := (*S.values)[i]
+		values = append(values, fmt.Sprintf("%v", value))
+	}
+	return fmt.Sprintf(strings.Join(values, " -> "))
+}
+
+func (S QueueInt) EMPTY() bool {
+	return S.Length() == 0
+}
+
+func (S *QueueInt) ENQUEUE(x int) {
+	if S.values == nil {
+		panic("Queue not initialised!")
+	}
+	*S.values = append(*S.values, x)
+}
+
+func (S *QueueInt) FRONT() int {
+	if S.EMPTY() {
+		panic("Cannot read from empty queue!")
+	}
+	return (*S.values)[0]
+}
+
+func (S *QueueInt) DEQUEUE() {
+	if S.EMPTY() {
+		panic("Cannot remove from empty queue!")
+	}
+	*S.values = (*S.values)[1:]
+}

code/golang/pkg/data_structures/stacks/stacks.go

@@ -20,7 +20,7 @@ import (
  * ---------------------------------------------------------------- */
 
 type StackInt struct {
-	values []int
+	values *[]int
 }
 
 /* ---------------------------------------------------------------- *
@@ -28,45 +28,54 @@ type StackInt struct {
  * ---------------------------------------------------------------- */
 
 func CREATE() StackInt {
-	return StackInt{
-		values: []int{},
+	return StackInt{}
+}
+
+func (S *StackInt) INIT() {
+	S.values = &[]int{}
+}
+
+func (S StackInt) Length() int {
+	if S.values == nil {
+		return 0
 	}
-}
-
-func (S *StackInt) INIT() StackInt {
-	return StackInt{
-		values: []int{},
-	}
-}
-
-func (S StackInt) EMPTY() bool {
-	return len(S.values) == 0
-}
-
-func (S *StackInt) PUSH(x int) {
-	S.values = append(S.values, x)
-}
-
-func (S *StackInt) TOP() int {
-	if S.EMPTY() {
-		panic("Cannot pop from empty stack!")
-	}
-	return S.values[len(S.values)-1]
-}
-
-func (S *StackInt) POP() int {
-	x := S.TOP()
-	S.values = S.values[:(len(S.values) - 1)]
-	return x
+	return len(*S.values)
 }
 
 func (S StackInt) String() string {
-	if len(S.values) == 0 {
+	if S.EMPTY() {
 		return "-"
 	}
 	values := []string{}
-	for _, value := range S.values {
+	for _, value := range *S.values {
 		values = append(values, fmt.Sprintf("%v", value))
 	}
 	return fmt.Sprintf(strings.Join(values, ", "))
 }
+
+func (S StackInt) EMPTY() bool {
+	return S.Length() == 0
+}
+
+func (S *StackInt) PUSH(x int) {
+	if S.values == nil {
+		panic("Stack not initialised!")
+	}
+	*S.values = append(*S.values, x)
+}
+
+func (S *StackInt) TOP() int {
+	if S.EMPTY() {
+		panic("Cannot read from empty stack!")
+	}
+	n := S.Length()
+	return (*S.values)[n-1]
+}
+
+func (S *StackInt) POP() {
+	if S.EMPTY() {
+		panic("Cannot remove from empty stack!")
+	}
+	n := S.Length()
+	*S.values = (*S.values)[:(n - 1)]
+}