Implement Priority Queue

循环队列

复盘:

isFull 的地方遗漏了取余操作 , rear 的边界处理没想到

画图的时候没走完整可能性 , 下次画的时候可以每走一步,根据图和伪代码执行一次所有函数

定义

data 存放数据的有限长度数组
head 指向队列头的第一个元素, 初始化0
tail 指向队列尾的最后一个元素 初始化 0
cap 容量 = len(data) -1
dataLen  数组长度

画图

入队

data[tail] = number
tail = tail++  % dataLen
return 

LeetCode 循环队列 LeetCode 循环队列

出队

if this.isEmpty() throw Exception

res=data[head]
head=head+1 % dataLen
return res

LeetCode 循环队列

tail 循环

LeetCode 循环队列

队列满状态

if (tail+1)%dataLen==head

LeetCode 循环队列

队列空状态

if head==tail

LeetCode 循环队列
LeetCode 循环队列

Accepted:

type MyCircularQueue struct {
    data []int
    head int
    tail int
    cap  int
    len  int
}

/** Initialize your data structure here. Set the size of the queue to be k. */
func Constructor(k int) MyCircularQueue {
    q := MyCircularQueue{data: make([]int, k+1), head: 0, tail: 0, cap: k, len: k+1}
    return q
}

/** Insert an element into the circular queue. Return true if the operation is successful. */
func (this *MyCircularQueue) EnQueue(value int) bool {
    if this.IsFull() {
        return false
    }
    this.data[this.tail] = value
    this.tail=(this.tail+1) % this.len
    return true
}

/** Delete an element from the circular queue. Return true if the operation is successful. */
func (this *MyCircularQueue) DeQueue() bool {
    if this.IsEmpty() {
        return false
    }
    //res:=this.data[head]
    this.head=(this.head+1) % this.len
    return true
}

/** Get the front item from the queue. */
func (this *MyCircularQueue) Front() int {
    if this.IsEmpty() {
        return -1
    }
    return this.data[this.head]
}

/** Get the last item from the queue. */
func (this *MyCircularQueue) Rear() int {
    if this.IsEmpty() {
        return -1
    }
    if this.tail==0 {
        return this.data[this.len-1]
        
    }
    return this.data[(this.tail-1)%this.len]
}

/** Checks whether the circular queue is empty or not. */
func (this *MyCircularQueue) IsEmpty() bool {
    if this.head==this.tail {
        return true

    }
    return false

}

/** Checks whether the circular queue is full or not. */
func (this *MyCircularQueue) IsFull() bool {
    if (this.tail+1)%this.len==this.head {
        return true
    }
    return false
}