155. Min Stack

原题链接：https://leetcode.com/problems/min-stack/description/
这道题目就是考察基本的栈概念的吧，没什么难度：

/**
 * Created by clearbug on 2018/3/17.
 */
public class MinStack {

    private int min;

    private int[] elements;

    private int count;

    /** initialize your data structure here. */
    public MinStack() {
        min = Integer.MAX_VALUE;
        elements = new int[10];
    }

    public void push(int x) {
        if (x < min) {
            min = x;
        }

        if (count == elements.length) {
            int[] newElements = new int[2 * elements.length];
            System.arraycopy(elements, 0, newElements, 0, elements.length);
            elements = newElements;
        }
        elements[count++] = x;
    }

    public void pop() {
        count--;
        min = Integer.MAX_VALUE;
        for (int i = 0; i < count; i++) {
            if (elements[i] < min) {
                min = elements[i];
            }
        }
    }

    public int top() {
        return elements[count - 1];
    }

    public int getMin() {
        return min;
    }

}