Daily LeetCode – day0017 0641. Design Circular Deque

// 0641. Design Circular Deque
class MyCircularDeque {

    private final int[] values;
    private final int capacity;
    private int size;
    private int f;
    private int r;

    public MyCircularDeque(int k) {
        values = new int[k];
        capacity = k;
        size = 0;
        f = 0;
        r = 0;
    }

    public boolean insertFront(int value) {
        if (size == capacity) return false;
        if (size != 0) f = (f + 1) % capacity;
        values[f] = value;
        ++size;
        return true;
    }

    public boolean insertLast(int value) {
        if (size == capacity) return false;
        if (size != 0) r = (r + capacity - 1) % capacity;
        values[r] = value;
        ++size;
        return true;
    }

    public boolean deleteFront() {
        if (size == 0) return false;
        if (size != 1) f = (f + capacity - 1) % capacity;
        --size;
        return true;
    }

    public boolean deleteLast() {
        if (size == 0) return false;
        if (size != 1) r = (r + 1) % capacity;
        --size;
        return true;
    }

    public int getFront() {
        if (size == 0) return -1;
        return values[f];
    }

    public int getRear() {
        if (size == 0) return -1;
        return values[r];
    }

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

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

学习笔记：
和之前循环队列差的不多，可以先把图在iPad上画出来，然后推演各种情况。
但是还是有不少的bug，所以细心真的很重要，我这跑了很多很多遍才全部跑通。