AcWing 20. 用两个栈实现队列
原题链接
简单
作者:
辰兩
,
2023-11-14 21:55:42
,
所有人可见
,
阅读 42
C++ 代码
class MyQueue {
public:
stack <int>s1,s2;
/** Initialize your data structure here. */
MyQueue() {
}
/** Push element x to the back of queue. */
void push(int x) {
s1.push(x);
}
/** Removes the element from in front of queue and returns that element. */
int pop() {
while(! s1.empty())
{
int a = s1.top();
s2.push(a);
s1.pop();
}
int s = s2.top();
s2.pop();
while(!s2.empty())
{
int a = s2.top();
s1.push(a);
s2.pop();
}
return s;
}
/** Get the front element. */
int peek() {
while (! s1.empty())
{
int a = s1.top();
s2.push(a);
s1.pop();
}
int s = s2.top();
while (! s2.empty())
{
int a = s2.top();
s1.push(a);
s2.pop();
}
return s;
}
/** Returns whether the queue is empty. */
bool empty() {
return s1.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();
*/