Create 641. Design Circular Deque (#598)

Author: Chayandas07

641. Design Circular Deque

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+class MyCircularDeque {
+public:
+    const int k;
+    vector<int> q;
+    int size = 0;
+    int front = 0;
+    int rear;
+    MyCircularDeque(int k): k(k), q(k), rear(k - 1){
+        
+    }
+    
+    bool insertFront(int value) {
+        if(isFull()){
+            return false;
+        }
+        front = (--front + k) % k;
+        q[front] = value;
+        size++;
+        return true;
+    }
+    
+    bool insertLast(int value) {
+        if(isFull()){
+            return false;
+        }
+        rear = ++rear % k;
+        q[rear] = value;
+        size++;
+        return true;
+    }
+    
+    bool deleteFront() {
+        if(isEmpty()){
+            return false;
+        }
+        front = ++front % k;
+        size--;
+        return true;
+    }
+    
+    bool deleteLast() {
+        if(isEmpty()){
+            return false;
+        }
+        rear = (--rear + k)%k;
+        size--;
+        return true;
+    }
+    
+    int getFront() {
+        return isEmpty() ? -1 : q[front];
+    }
+    
+    int getRear() {
+        return isEmpty() ? -1 : q[rear];
+    }
+    
+    bool isEmpty() {
+        return size == 0;
+    }
+    
+    bool isFull() {
+        return size == k;
+    }
+};