【剑指OFFER】包含min函数的栈

 1 import java.util.Stack;
 2 
 3 public class Solution {
 4 
 5     Stack<Integer> dataStack = new Stack<>();
 6     Stack<Integer> minStack = new Stack<>();
 7     
 8     public void push(int node) {
 9         dataStack.push(node);
10         if (minStack.isEmpty() || node < minStack.peek())
11             minStack.push(node);
12         else minStack.push(minStack.peek());
13     }
14     
15     public void pop() {
16         dataStack.pop();
17         minStack.pop();
18     }
19     
20     public int top() {
21         return dataStack.peek();
22     }
23     
24     public int min() {
25         return minStack.peek();
26     }
27 }