LeetCode: Min Stack

LeetCode: Min Stack 

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/**
 * Created by hzhou on 4/24/15. [email protected]
 */
public class MinStack {
    private Stack<Integer> stack = new Stack<Integer>();
    private Stack<Integer> minStack = new Stack<Integer>();
    public void push(int x) {
        stack.push(x);
        if (minStack.isEmpty() || x <= minStack.peek()) {
            minStack.push(x);
        }
    }
    public void pop() {
        int val = stack.pop();
        if (val <= minStack.peek()) {
            minStack.pop();
        }
    }
    public int top() {
        return stack.peek();
    }
    public int getMin() {
        return minStack.peek();
    }
}