155.最小栈

`

class MinStack{
Deque stack;
Deque minStack;
int min = Integer.MAX_VALUE;
public MinStack() {
stack = new ArrayDeque<>();
minStack = new ArrayDeque<>();
}

public void push(int val) {
stack.push(val);
if(val<min){
minStack.push(val);
min = val;
}else{
minStack.push(min);
}
}

public void pop() {
stack.pop();
minStack.pop();
if(minStack.isEmpty()){
min = Integer.MAX_VALUE;
return;
}
min = minStack.peek();
}

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

public int getMin() {
return min;
}
}`