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refactor 232
1 parent 313e8e1 commit 7be27a7

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  • src/main/java/com/fishercoder/solutions

1 file changed

+32
-24
lines changed
Lines changed: 32 additions & 24 deletions
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package com.fishercoder.solutions;
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import java.util.Stack;
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/**Implement the following operations of a queue using stacks.
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/**
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* 232. Implement Queue using Stacks
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*
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* Implement the following operations of a queue using stacks.
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push(x) -- Push element x to the back of queue.
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pop() -- Removes the element from in front of queue.
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peek() -- Get the front element.
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empty() -- Return whether the queue is empty.
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Notes:
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You must use only standard operations of a stack -- which means only push to top, peek/pop from top, size, and is empty operations are valid.
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Depending on your language, stack may not be supported natively. You may simulate a stack by using a list or deque (double-ended queue), as long as you use only standard operations of a stack.
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You may assume that all operations are valid (for example, no pop or peek operations will be called on an empty queue).*/
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You may assume that all operations are valid (for example, no pop or peek operations will be called on an empty queue).
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*/
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public class _232 {
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class MyQueue {
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public static class Solution1 {
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class MyQueue {
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Stack<Integer> input = new Stack();
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Stack<Integer> output = new Stack();
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Stack<Integer> input = new Stack();
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Stack<Integer> output = new Stack();
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// Push element x to the back of queue.
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public void push(int x) {
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input.push(x);
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}
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// Push element x to the back of queue.
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public void push(int x) {
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input.push(x);
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}
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// Removes the element from in front of queue.
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public int pop() {
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peek();
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return output.pop();
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}
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// Removes the element from in front of queue.
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public int pop() {
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peek();
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return output.pop();
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}
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// Get the front element.
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public int peek() {
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if (output.isEmpty()) {
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while (!input.isEmpty()) {
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output.push(input.pop());
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// Get the front element.
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public int peek() {
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if (output.isEmpty()) {
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while (!input.isEmpty()) {
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output.push(input.pop());
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}
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}
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return output.peek();
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}
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return output.peek();
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}
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// Return whether the queue is empty.
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public boolean empty() {
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return input.isEmpty() && output.isEmpty();
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// Return whether the queue is empty.
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public boolean empty() {
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return input.isEmpty() && output.isEmpty();
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}
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}
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}
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}
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