两个栈实现一个队列
import java.util.EmptyStackException;
import java.util.Stack;
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(stack1.empty()){
throw new EmptyStackException();
}
while(!stack1.empty()){
int temp = stack1.pop();
stack2.push(temp);
}
int a = stack2.pop();
while(!stack2.empty()){
int temp = stack2.pop();
stack1.push(temp);
}
return a;
}
}
两个队列实现一个栈
import java.util.Deque;
import java.util.LinkedList;
import java.util.NoSuchElementException;
class Solution {
Deque<Integer> list1 =
new LinkedList<Integer>();
Deque<Integer> list2 =
new LinkedList<Integer>();
public void push(
int node){
list1.add(node);
}
public int pop(){
if(list1.isEmpty()){
throw new NoSuchElementException();
}
while(list1.size()!=
1){
int temp = list1.pop();
list2.add(temp);
}
int a = list1.pop();
while(!list2.isEmpty()){
int temp = list2.pop();
list1.add(temp);
}
return a;
}
}
