wip

Author: hdev14

dequeues/resized_dequeue.c

@@ -1,10 +1,118 @@
-typedef struct Dequeue
+// TODO: finish implementation
+#include <stdio.h>
+#include <stdbool.h>
+#include <malloc.h>
+
+typedef struct
 {
     int *items;
+    int start_idx;
+    int end_idx;
     int size;
 } Dequeue;
 
+void startdequeue(Dequeue *dequeue)
+{
+    dequeue->items = NULL;
+    dequeue->size = 0;
+    dequeue->start_idx = 0;
+    dequeue->end_idx = 0;
+}
+
+bool isEmpty(Dequeue *dequeue)
+{
+    return dequeue->items == NULL;
+}
+
+int getLength(Dequeue *dequeue)
+{
+    return sizeof(dequeue->items) / sizeof(int);
+}
+
+void printDequeue(Dequeue *dequeue)
+{
+    int idx = dequeue->start_idx;
+    int length = getLength(dequeue);
+
+    printf("dequeue\n");
+
+    for (int i = 0; i < dequeue->size; i++)
+    {
+        printf("%i ", dequeue->items[idx]);
+        idx = (idx + 1) % length;
+    }
+
+    printf("\n");
+}
+
+void resize(Dequeue *dequeue, int length)
+{
+    int new_length = length == 0 ? 1 : 2 * length;
+    int *new_items = (int *)malloc(sizeof(int) * new_length);
+
+    if (dequeue->size > 0)
+    {
+        for (int i = 0; i < length; i++)
+        {
+            new_items[i] = dequeue->items[i];
+        }
+    }
+
+    dequeue->items = new_items;
+}
+
+bool insertItem(Dequeue *dequeue, int item)
+{
+    int length = isEmpty(dequeue) ? 0 : getLength(dequeue);
+
+    if (dequeue->size == length)
+    {
+        resize(dequeue, length);
+        length = getLength(dequeue);
+    }
+
+    int idx = (dequeue->start_idx + dequeue->size) % length;
+    dequeue->items[idx] = item;
+    dequeue->size++;
+    return false;
+}
+
+bool removeItem(Dequeue *dequeue, int *item)
+{
+    if (dequeue->size == 0)
+    {
+        return false;
+    }
+
+    *item = dequeue->items[dequeue->start_idx];
+    dequeue->items[dequeue->start_idx] = NULL;
+    dequeue->start_idx = (dequeue->start_idx + 1) % getLength(dequeue);
+    return true;
+}
+
 int main()
 {
+
+    Dequeue dequeue;
+    startdequeue(&dequeue);
+
+    for (int i = 0; i < 5; i++)
+    {
+        insertItem(&dequeue, i + 1);
+    }
+
+    printDequeue(&dequeue);
+
+    printf("dequeue size => %i \n", dequeue.size);
+
+    for (int i = 0; i < 5 / 2; i++)
+    {
+        int item;
+        removeItem(&dequeue, &item);
+        printf("%i ", item);
+    }
+
+    printDequeue(&dequeue);
+
     return 0;
 }