Added circular deque

varunu28 · varunu28 · commit 9ebe6ce87b1a · 2018-09-21T21:23:00.000-07:00
diff --git a/Medium/Design Circular Deque.java b/Medium/Design Circular Deque.java
@@ -0,0 +1,129 @@
+class MyCircularDeque {
+
+    /** Initialize your data structure here. Set the size of the deque to be k. */
+    Queue<Integer> main;
+    Queue<Integer> backup;
+    int capacity;
+    
+    public MyCircularDeque(int k) {
+        main = new LinkedList<>();
+        backup = new LinkedList<>();
+        capacity = k;
+    }
+    
+    /** Adds an item at the front of Deque. Return true if the operation is successful. */
+    public boolean insertFront(int value) {
+        if (main.size() == capacity) {
+            return false;
+        }
+        
+        while(!main.isEmpty()) {
+            backup.add(main.remove());
+        }
+        
+        main.add(value);
+        
+        while (!backup.isEmpty()) {
+            main.add(backup.remove());
+        }
+        
+        return true;
+    }
+    
+    /** Adds an item at the rear of Deque. Return true if the operation is successful. */
+    public boolean insertLast(int value) {
+        if (main.size() == capacity) {
+            return false;
+        }
+        
+        main.add(value);
+        
+        return true;
+    }
+    
+    /** Deletes an item from the front of Deque. Return true if the operation is successful. */
+    public boolean deleteFront() {
+        if (main.isEmpty()) {
+            return false;
+        }
+        
+        main.remove();
+        
+        return true;
+    }
+    
+    /** Deletes an item from the rear of Deque. Return true if the operation is successful. */
+    public boolean deleteLast() {
+        if (main.isEmpty()) {
+            return false;
+        }
+        
+        while(!main.isEmpty()) {
+            backup.add(main.remove());
+        }
+        
+        int size = backup.size();
+        
+        while (size-- > 1) {
+            main.add(backup.remove());
+        }
+        
+        backup.remove();
+        
+        return true;
+    }
+    
+    /** Get the front item from the deque. */
+    public int getFront() {
+        if (main.isEmpty()) {
+            return -1;
+        }
+        
+        return main.peek();
+    }
+    
+    /** Get the last item from the deque. */
+    public int getRear() {
+        if (main.isEmpty()) {
+            return -1;
+        }
+        
+        while(!main.isEmpty()) {
+            backup.add(main.remove());
+        }
+        
+        int size = backup.size();
+        
+        while (size-- > 1) {
+            main.add(backup.remove());
+        }
+        
+        int ans = backup.peek();
+        main.add(backup.remove());
+        
+        return ans;
+    }
+    
+    /** Checks whether the circular deque is empty or not. */
+    public boolean isEmpty() {
+        return main.isEmpty();
+    }
+    
+    /** Checks whether the circular deque is full or not. */
+    public boolean isFull() {
+        return main.size() == capacity;
+    }
+}
+
+/**
+ * Your MyCircularDeque object will be instantiated and called as such:
+ * MyCircularDeque obj = new MyCircularDeque(k);
+ * boolean param_1 = obj.insertFront(value);
+ * boolean param_2 = obj.insertLast(value);
+ * boolean param_3 = obj.deleteFront();
+ * boolean param_4 = obj.deleteLast();
+ * int param_5 = obj.getFront();
+ * int param_6 = obj.getRear();
+ * boolean param_7 = obj.isEmpty();
+ * boolean param_8 = obj.isFull();
+ */
