用两个栈实现队列

题目描述

class Solution
{
public:
void push(int node) {
stack1.push(node);
}

int pop() {
if(stack2.size()<=0){
while(stack1.size()){
int data = stack1.top();
stack1.pop();
stack2.push(data);
}
}
int head = stack2.top();
stack2.pop();
return head;
}

private:
stack<int> stack1;
stack<int> stack2;
};