AcWing 20. 用两个栈实现队列
原题链接
简单
作者:
Curran
,
2021-07-07 22:10:52
,
所有人可见
,
阅读 836
class MyQueue
{
public:
/** Initialize your data structure here. */
stack<int> stk,cache;
MyQueue()
{
}
/** Push element x to the back of queue. */
void push(int x)
{
stk.push(x);
}
void copy(stack<int>&a,stack<int>&b)
{
while (a.size())
{
b.push(a.top());
a.pop();
}
}
/** Removes the element from in front of queue and returns that element. */
int pop()
{
copy(stk,cache);
int res=cache.top();
cache.pop();
copy(cache,stk);
return res;
}
/** Get the front element. */
int peek()
{
copy(stk,cache);
int res=cache.top();
copy(cache,stk);
return res;
}
/** Returns whether the queue is empty. */
bool empty()
{
return stk.empty();
}
};
/**
* Your MyQueue object will be instantiated and called as such:
* MyQueue obj = MyQueue();
* obj.push(x);
* int param_2 = obj.pop();
* int param_3 = obj.peek();
* bool param_4 = obj.empty();
*/