g0601_0700.s0622_design_circular_queue.MyCircularQueue Maven / Gradle / Ivy

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Java-based LeetCode algorithm problem solutions, regularly updated

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package g0601_0700.s0622_design_circular_queue;

// #Medium #Array #Design #Linked_List #Queue

public class MyCircularQueue {
    private final DoubleLinkedNode dumyHead = new DoubleLinkedNode(0);
    private final int maxSize;
    private int size = 0;

    public MyCircularQueue(int k) {
        this.maxSize = k;
        dumyHead.left = dumyHead;
        dumyHead.right = dumyHead;
    }

    public boolean enQueue(int value) {
        if (size == maxSize) {
            return false;
        }
        DoubleLinkedNode node = new DoubleLinkedNode(value);
        DoubleLinkedNode right = dumyHead.right;
        dumyHead.right = node;
        node.left = dumyHead;
        node.right = right;
        right.left = node;
        size++;
        return true;
    }

    public boolean deQueue() {
        if (size == 0) {
            return false;
        }
        DoubleLinkedNode left = dumyHead.left;
        dumyHead.left = left.left;
        dumyHead.left.right = dumyHead;
        size--;
        return true;
    }

    public int rear() {
        if (size == 0) {
            return -1;
        }
        return dumyHead.right.val;
    }

    public int front() {
        if (size == 0) {
            return -1;
        }
        return dumyHead.left.val;
    }

    public boolean isEmpty() {
        return size == 0;
    }

    public boolean isFull() {
        return size == maxSize;
    }

    static class DoubleLinkedNode {
        private final int val;
        private DoubleLinkedNode left;
        private DoubleLinkedNode right;

        public DoubleLinkedNode(int val) {
            this.val = val;
        }
    }
}