Re: [閒聊] 每日leetcode

[Rushia (早瀬ユウカの体操服 )]

https://leetcode.com/problems/design-circular-deque/description
641. Design Circular Deque
設計一個雙邊佇列

思路：
1.照題目敘述設計，因為只關注前後所以用鏈結串列保存串列的頭尾就好。


java code
-----------------------------------------------------------------
class MyCircularDeque {
    int k;
    int size;
    Node first;
    Node last;
    public MyCircularDeque(int k) {
        this.k = k;
        this.size = 0;
    }

    public boolean insertFront(int value) {
        if (isFull()) return false;
        Node node = new Node(value);
        if (isEmpty()) {
            last = first = node;
        } else {
            node.next = first;
            first.prev = node;
            first = node;
        }
        size++;
        return true;
    }
    public boolean insertLast(int value) {
        if (isFull()) return false;
        Node node = new Node(value);
        if (isEmpty()) {
            last = first = node;
        } else {
            last.next = node;
            node.prev = last;
            last = node;
        }
        size++;
        return true;
    }

    public boolean deleteFront() {
        if (isEmpty()) return false;
        size--;
        first = first.next;
        if (first != null) {
            first.prev = null;
        }
        return true;
    }

    public boolean deleteLast() {
        if (isEmpty()) return false;
        size--;
        last = last.prev;
        if (last != null) {
            last.next = null;
        }
        return true;
    }

    public int getFront() {
        if (isEmpty()) return -1;
        return first.val;
    }

    public int getRear() {
        if (isEmpty()) return -1;
        return last.val;
    }

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

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

}
class Node {
    int val;
    Node prev;
    Node next;
    public Node(int val) {
        this.val = val;
    }
}
-----------------------------------------------------------------

--
你跟我說這個我有什麼辦法
https://i.imgur.com/wb5zrOy.jpeg

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