算法刷题(26)_包含min函数的栈_学习记录

package p29;

import java.util.Stack;

/**
 * 包含min函数的栈
 * @author Guozhu Zhu
 * @date 2018/8/19
 * @version 1.0
 *
 */
public class Test04 {
	
	public Stack<Integer> data = new Stack<Integer>();    //存储数据的栈
	 
	public Stack<Integer> min = new Stack<Integer>();     //存储栈最小值的栈
	
	public Integer temp;                                  //存储栈最小值的临时标记元素
	
	public void push(int node) {
		if (temp != null) {
			if (node < temp) {
				temp = node;
				min.push(temp);
			}
			data.push(node);
		} else {
			temp = node;
			data.push(node);
			min.push(node);
		}
	}
	     
	public void pop() {
		int num1 = data.pop();
		int num2 = min.pop();
		//若两元素不等，则最小值还在数据栈中，所以还要push回去；
		if (num1 != num2) {
			min.push(num2);
		}
	}
	
	public int top() {
		return data.peek();
	}
	
	public int min() {
		return min.peek();
	}
	
	public static void main(String[] args) {
		Test04 minStack = new Test04();
		minStack.push(1);
		minStack.push(2);
		minStack.push(3);
		System.out.println(minStack.min());
	}

}