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ImplementQueueusingStacks.java
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ImplementQueueusingStacks.java
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package stack;
import java.util.Stack;
//https://leetcode.com/problems/implement-queue-using-stacks/
public class ImplementQueueusingStacks {
}
class MyQueue {
Stack<Integer> s1=null;
Stack<Integer> s2= null;
/** Initialize your data structure here. */
public MyQueue() {
s1= new Stack<Integer>();
s2= new Stack<Integer>();
}
/** Push element x to the back of queue. */
public void push(int x) {
while(!s1.isEmpty()){
s2.push(s1.pop());
}
s2.push(x);
while(!s2.isEmpty()){
s1.push(s2.pop());
}
}
/** Removes the element from in front of queue and returns that element. */
public int pop() {
return s1.pop();
}
/** Get the front element. */
public int peek() {
return s1.peek();
}
/** Returns whether the queue is empty. */
public boolean empty() {
return s1.isEmpty();
}
}
/**
* Your MyQueue object will be instantiated and called as such:
* MyQueue obj = new MyQueue();
* obj.push(x);
* int param_2 = obj.pop();
* int param_3 = obj.peek();
* boolean param_4 = obj.empty();
*/