class MyQueue {
stack<int> s1;
stack<int> s2;
int front;
public:
/** Initialize your data structure here. */
MyQueue() {
}
/** Push element x to the back of queue. */
void push(int x) {
if(s1.empty()) front = x;
s1.push(x);
}
/** Removes the element from in front of queue and returns that element. */
int pop() {
while(!s1.empty()) {
s2.push(s1.top());
s1.pop();
}
int res = s2.top();
s2.pop();
if(!s2.empty())
front = s2.top();
while(!s2.empty()) {
s1.push(s2.top());
s2.pop();
}
return res;
}
/** Get the front element. */
int peek() {
return front;
}
/** Returns whether the queue is empty. */
bool empty() {
return s1.empty();
}
};
/**
* Your MyQueue object will be instantiated and called as such:
* MyQueue* obj = new MyQueue();
* obj->push(x);
* int param_2 = obj->pop();
* int param_3 = obj->peek();
* bool param_4 = obj->empty();
*/
