【16】双栈排序

import java.util.*;

public class TwoStacks {
    public ArrayList<Integer> twoStacksSort(int[] numbers) {

        ArrayList<Integer> list = new ArrayList<Integer>();
        
        //构建栈，并初始化栈
        Stack<Integer> initStack = new Stack<>();
        for (int i = 0 ; i < numbers.length; i++){
            initStack.push(numbers[i]);
        }
        
        //构建辅助栈,用来存放排好序的数
        Stack<Integer> tempStack = new Stack<>();
        while(!initStack.isEmpty()){
            
            if (tempStack.isEmpty()){
                tempStack.push(initStack.pop());
            }else {
                //新建变量，存储原始栈中待排序的栈
                int tmp = initStack.pop();
                
                //将辅助栈中的排好序中的大于tmp的数放入原始栈中
                while (!tempStack.isEmpty() && tempStack.peek() > tmp){
                    initStack.push(tempStack.pop());
                }
                //辅助栈存储之前保存的变量
                tempStack.push(tmp);
                
            }
            
            
        }
        
        while(!tempStack.isEmpty()){
            list.add(tempStack.pop());
        }
        
        return list;
    }
}