Sword refers to offer: Face Test 21--contains the Min function stack (Java implementation) __java

Problem Description:

To define the data structure of the stack, implement a min function in the type that can get the smallest element of the stack. In this stack, the time complexity of calling Min,push and POPs is O (1).

Idea: Add a secondary stack to store the minimum set of values

(here to pay attention to the topic does not say the stack of element types, so try to general)

Import Java.util.Stack;

public class Solution {


    stack s1=new stack ();
    Stack min=new stack ();
    public void push (int node) {
        if (Min.empty ()) {
            Min.push (node);
        } else{
            int top= (int) min.peek ();
            if (node<top) {
               Min.push (node);
            } else{
                Min.push (top);
            }
        S1.push (node);
    }

    public void Pop () {
        if (! S1.empty ()) {
            s1.pop ());
            Min.pop ();
        }

    public int Top () {return
        (int) s1.peek ();
    }

    public int min () {
       if (Min.empty ()) {return
           0;
       }
       return (int) min.peek ();    
    }





}