数据结构：设计一个具有getMin的栈

数据结构

版本：2
作者：陈小默
声明：禁止商业，禁止转载

使用任意语言设计一个栈，要求具有如下功能：

• 使用pop出栈
• 使用push入栈
• 使用getMin获取栈中最小值

设计思路：使用两个栈结构

/**
 *  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 16/11/5.
 */
class GetMinStack(max: Int) {
    val stack = Stack<Int>(max)
    val min = Stack<Int>(max)
    fun getMin(): Int = min.top!!
    fun pop(): Int {
        val value = stack.pop()!!
        if (value == getMin()) {
            min.pop()
        }
        return value
    }
    fun push(value: Int) {
        stack.push(value)
        if (min.isEmpty || value <= getMin()) {
            min.push(value)
        }
    }
}