一、实现一个特殊的栈，在实现栈的基本功能的基础上，再实现返回栈中最小元素的操作

请指教交流！

 1 package com.it.hxs.c01;
 2
 3 import java.util.Stack;
 4
 5 /*
 6  实现一个特殊的栈，在实现栈的基本功能的基础上，再实现返回栈中最小元素的操作
 7  */
 8 public class GetMinStack {
 9
10     public static void main(String args[]) {
11         GetMinStack demoStack = new GetMinStack();
12         demoStack.push("1");
13         demoStack.push("2");
14         demoStack.push("");
15         System.out.println(demoStack.getMin());
16         System.out.println(demoStack.pop());
17         System.out.println(demoStack.getMin());
18     }
19
20     private Stack<String> stringStack;
21     private Stack<Integer> intStack;
22     private Stack<String> minStack;
23
24     public GetMinStack() {
25         this.stringStack = new Stack<String>();
26         this.intStack = new Stack<Integer>();
27         this.minStack = new Stack<String>();
28     }
29
30     public void push(String content) {
31         if ("".equals(content)||content == null) {
32             throw new RuntimeException("添加的元素值不能为空！");
33         } else {
34             int data = string2ASCII(content);
35             stringStack.push(content);
36             if (!intStack.isEmpty()) {
37                 int curIntStackData = intStack.peek();
38                 if (curIntStackData >= data) {// 数值栈intStack中最上面元素大于当前推入元素，则当前元素为最小，则当前元素推入最小元素栈minStack
39                     minStack.push(content);
40                 } else {
41                     minStack.push(minStack.peek());
42                 }
43             } else {
44                 minStack.push(content);
45             }
46             intStack.push(data);
47         }
48     }
49
50     public String pop() {
51         String result = "无元素";
52         if (!intStack.isEmpty()) {
53             intStack.pop();
54         }
55         if (!minStack.isEmpty()) {
56             minStack.pop();
57         }
58         if (!stringStack.isEmpty()) {
59             result = stringStack.pop();
60         }
61         return result;
62     }
63
64     public String getMin() {
65         String result = "无元素";
66         if (!minStack.isEmpty()) {
67             result = minStack.peek();
68         }
69         return result;
70     }
71
72     // 字符串转ASCII
73     public static int string2ASCII(String content) {
74         int result = 0;
75         char[] chars = content.toCharArray();
76         for (char c : chars) {
77             int temp = (int) c;
78             result = result + temp;
79         }
80         return result;
81     }
82
83 }