数据结构 -- 栈

Posted 2020-10-15 limeOracle

1. 实现一个栈，可以在最小时间复杂度内计算出栈中的最小值。空间复杂度无视。

package lime.xiaoniu;

import java.util.Iterator;
import java.util.Stack;

/**
 * 实现一个栈，可以在最小时间复杂度内计算出栈中的最小值。空间复杂度无视。
 */
public class DevilStack {
    public static void main(String[] args){
        DevilStack stack = new DevilStack();
        for(int i = 10;i > 0;i--){
            stack.push((int)(Math.random() * 100));
        }
        stack.inOrder();
        while (!stack.isEmpty()){
            System.out.println("mixStackPop : " + stack.peekMixData() + " dataStackPop : " + stack.pop());
        }
    }
    private Stack<Integer> dataStack = new Stack<Integer>();
    private Stack<Integer> mixStack = new Stack<Integer>();
    private Integer mixData = Integer.MAX_VALUE;

    public boolean push(Integer data){
        if(null == data){
            return false;
        }
        dataStack.push(data);
        mixStack.push(mixData = Math.min(mixData,data));
        return true;
    }
    public Integer pop(){
        if(dataStack.isEmpty()){
            return null;
        }
        mixStack.pop();
        return dataStack.pop();
    }
    public Integer peekMixData(){
        if(dataStack.isEmpty()){
            return null;
        }
        return mixStack.peek();
    }
    public void inOrder(){
        if(dataStack.isEmpty()){
            return;
        }
        Iterator<Integer> iterator = dataStack.iterator();
        System.out.print("dataStack : " );
        for(;iterator.hasNext();){
            System.out.print(iterator.next() + "  ");
        }
        System.out.print("\nmixStack : ");
        for(iterator = mixStack.iterator();iterator.hasNext();){
            System.out.print(iterator.next() + "  ");
        }
        System.out.println();
    }
    public boolean isEmpty(){
        return dataStack.isEmpty();
    }
}

啦啦啦