【Leetcode】Min Stack

标签：java   leetcode   minstack   

Design a stack that supports push, pop, top, and retrieving the minimum element in constant time.

• push(x) -- Push element x onto stack.
• pop() -- Removes the element on top of the stack.
• top() -- Get the top element.

• getMin() -- Retrieve the minimum element in the stack

import java.util.ArrayList;
import java.util.Stack;

class MinStack {
Stack<Integer> stack = new Stack<Integer>();
int min;

public static void main(String args[]){
MinStack ms  = new MinStack();
ms.push(0);
ms.push(1);
ms.push(0);
System.out.println(ms.getMin());
ms.pop();
//System.out.println(ms.pop(););
System.out.println(ms.getMin());
}

    public void push(int x) {
    
if(stack.empty()||x<=min){
    
stack.push(min);
    
stack.push(x);
    
min = x;
    
}
    
else stack.push(x);
    }

    public void pop() {
    
int tmp = stack.pop();
    
if(tmp==min)
min=stack.pop();
    }

    public int top() {
        return stack.peek();
    }

    public int getMin() {
        return min;
    }
}

【Leetcode】Min Stack

标签：java   leetcode   minstack   

原文地址：http://blog.csdn.net/qbt4juik/article/details/41720321