题解 | #用两个栈实现队列#
用两个栈实现队列
http://www.nowcoder.com/practice/54275ddae22f475981afa2244dd448c6
通过画图,将问题形象化
思路:出栈时,若stack2为空,将stack1中的全部挪入stack2;若不为空,则直接stack2.pop()
import java.util.Stack;
public class Solution {
Stack<Integer> stack1 = new Stack<Integer>();
Stack<Integer> stack2 = new Stack<Integer>();
public void push(int node) {
stack1.push(node);
}
public int pop() {
if(stack2.isEmpty()){
while(!stack1.isEmpty()){
stack2.push(stack1.pop());
}
}
return stack2.pop();
}
}