Design your implementation of the circular double-ended queue (deque).
Your implementation should support following operations:
-
MyCircularDeque(k): Constructor, set the size of the deque to be k. -
insertFront(): Adds an item at the front of Deque. Return true if the operation is successful. -
insertLast(): Adds an item at the rear of Deque. Return true if the operation is successful. -
deleteFront(): Deletes an item from the front of Deque. Return true if the operation is successful. -
deleteLast(): Deletes an item from the rear of Deque. Return true if the operation is successful. -
getFront(): Gets the front item from the Deque. If the deque is empty, return -1. -
getRear(): Gets the last item from Deque. If the deque is empty, return -1. -
isEmpty(): Checks whether Deque is empty or not. -
isFull(): Checks whether Deque is full or not.
Example:
MyCircularDeque circularDeque = new MycircularDeque(3); // set the size to be 3
circularDeque.insertLast(1); // return true
circularDeque.insertLast(2); // return true
circularDeque.insertFront(3); // return true
circularDeque.insertFront(4); // return false, the queue is full
circularDeque.getRear(); // return 2
circularDeque.isFull(); // return true
circularDeque.deleteLast(); // return true
circularDeque.insertFront(4); // return true
circularDeque.getFront(); // return 4
Note:
- All values will be in the range of [0, 1000].
- The number of operations will be in the range of [1, 1000].
- Please do not use the built-in Deque library.
Runtime: 112 ms, faster than 32.91% of Java online submissions for Design Circular Deque.
class MyCircularDeque {
private Deque<Integer> dq = new LinkedList<>();
private int cap;
/** Initialize your data structure here. Set the size of the deque to be k. */
public MyCircularDeque(int k) {
cap = k;
}
/** Adds an item at the front of Deque. Return true if the operation is successful. */
public boolean insertFront(int value) {
if(dq.size() == cap) return false;
dq.offerFirst(value);
return true;
}
/** Adds an item at the rear of Deque. Return true if the operation is successful. */
public boolean insertLast(int value) {
if(dq.size() == cap) return false;
dq.offerLast(value);
return true;
}
/** Deletes an item from the front of Deque. Return true if the operation is successful. */
public boolean deleteFront() {
if(dq.size() == ) return false;
dq.removeFirst();
return true;
}
/** Deletes an item from the rear of Deque. Return true if the operation is successful. */
public boolean deleteLast() {
if(dq.size() == ) return false;
dq.removeLast();
return true;
}
/** Get the front item from the deque. */
public int getFront() {
if(dq.size() == ) return -;
return dq.peekFirst();
}
/** Get the last item from the deque. */
public int getRear() {
if(dq.size() == ) return -;
return dq.peekLast();
}
/** Checks whether the circular deque is empty or not. */
public boolean isEmpty() {
return dq.size() == ;
}
/** Checks whether the circular deque is full or not. */
public boolean isFull() {
return dq.size() == cap;
}
}