数据结构：设计一个队列

数据结构

版本：1
作者：陈小默
声明：禁止商用，禁止转载

设计一个队列结构，要求使用数组实现循环队列

/**
 *  Copyright (C) <2016>  <陈小默>
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 *  Created by 陈小默 on 11/06.
 */
class Queue<E>(val max: Int) {
    val queue = Array<Any?>(max, { null })
    private var head = 0
    private var tail = 0
    var size = 0
        private set
    val isEmpty: Boolean get() = size == 0
    val isFull: Boolean get() = size == max
    /**
     * 添加数据到队列尾
     */
    fun add(e: E): Boolean {
        if (isFull)
            return false
        queue[tail] = e
        if (++tail >= max) tail = 0
        size++
        return true
    }
    /**
     * 移除队列头数据
     */
    fun poll(): E {
        if (isEmpty) throw RuntimeException("queue is empty")
        val value = queue[head] as E
        queue[head] = null
        if (++head >= max) head = 0
        size--
        return value
    }
    /**
     * 获取但不移除队列头数据
     */
    fun peek(): E {
        if (isEmpty) throw RuntimeException("queue is empty")
        return queue[head] as E
    }
}