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DesignCircularDeque.java
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DesignCircularDeque.java
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package com.algorithm.playground.leetcode.problems.lc600.lc640.lc641;
/**
* https://leetcode.com/problems/design-circular-deque/description/
*/
public class DesignCircularDeque {
public static MyCircularDeque myCircularDeque(int k) {
return new DesignCircularDeque().createMyCircularDeque(k);
}
private MyCircularDeque createMyCircularDeque(int k) {
return new MyCircularDeque(k);
}
class MyCircularDeque {
private Node head;
private Node tail;
private int size;
private int capacity;
/**
* Initialize your data structure here. Set the size of the deque to be k.
*/
public MyCircularDeque(int k) {
this.capacity = k;
head = new Node(-1);
tail = new Node(-1);
head.next = tail;
tail.prev = head;
}
/**
* Adds an item at the front of Deque. Return true if the operation is successful.
*/
public boolean insertFront(int value) {
if (isFull()) {
return false;
}
Node n = new Node(value, head, head.next);
head.next.prev = n;
head.next = n;
size++;
return true;
}
/**
* Adds an item at the rear of Deque. Return true if the operation is successful.
*/
public boolean insertLast(int value) {
if (isFull()) {
return false;
}
Node n = new Node(value, tail.prev, tail);
tail.prev.next = n;
tail.prev = n;
size++;
return true;
}
/**
* Deletes an item from the front of Deque. Return true if the operation is successful.
*/
public boolean deleteFront() {
if (isEmpty()) {
return false;
}
head.next.next.prev = head;
head.next = head.next.next;
size--;
return true;
}
/**
* Deletes an item from the rear of Deque. Return true if the operation is successful.
*/
public boolean deleteLast() {
if (isEmpty()) {
return false;
}
tail.prev.prev.next = tail;
tail.prev = tail.prev.prev;
size--;
return true;
}
/**
* Get the front item from the deque.
*/
public int getFront() {
return head.next.val;
}
/**
* Get the last item from the deque.
*/
public int getRear() {
return tail.prev.val;
}
/**
* Checks whether the circular deque is empty or not.
*/
public boolean isEmpty() {
return size == 0;
}
/**
* Checks whether the circular deque is full or not.
*/
public boolean isFull() {
return size == capacity;
}
private class Node {
int val;
Node prev, next;
public Node(int val) {
this.val = val;
}
public Node(int val, Node prev, Node next) {
this(val);
this.prev = prev;
this.next = next;
}
@Override
public String toString() {
return "Node{" +
"val=" + val +
", next=" + next +
'}';
}
}
}
}