Min stack

class MinStack {
    ArrayList<Integer> stack ;
    /** initialize your data structure here. */
    public MinStack() {
        stack = new ArrayList<>();
    }
    
    public void push(int x) {
        stack.add(x);
    }
    
    public void pop() {
        stack.remove(stack.size()-1);
    }
    
    public int top() {
        return stack.get(stack.size()-1);
    }
    
    public int getMin() {
        int o= Integer.MAX_VALUE;
        for(int i=0; i<stack.size(); i++)
            if(o>stack.get(i)) o= stack.get(i);
        return o;
    }
}

/**
 * Your MinStack object will be instantiated and called as such:
 * MinStack obj = new MinStack();
 * obj.push(x);
 * obj.pop();
 * int param_3 = obj.top();
 * int param_4 = obj.getMin();
 */