题目
class MyStack {
public:
queue<int> q;
/** Initialize your data structure here. */
MyStack() {
}
/** Push element x onto stack. */
void push(int x) {
q.push(x);
}
/** Removes the element on top of the stack and returns that element. */
int pop() {
int len = q.size();
while(len>1)
{
int x = q.front();
q.pop();
q.push(x);
len--;
}
int x=q.front();
q.pop();
return x;
}
/** Get the top element. */
int top() {
int x = pop();
q.push(x);
return x;
}
/** Returns whether the stack is empty. */
bool empty() {
return q.empty();
}
};
/**
* Your MyStack object will be instantiated and called as such:
* MyStack* obj = new MyStack();
* obj->push(x);
* int param_2 = obj->pop();
* int param_3 = obj->top();
* bool param_4 = obj->empty();
*/
