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Reverse digits of an integer. Example1: x = 123, return 321 Example2: x = -123, return -321 click to show spoilers. Note: The input is assumed to be a 32-bit signed integer. Your function

import java.util.ArrayList; import java.util.Random; public class sort { public static void main(String[] args){ System.out.println(get()); } public static ArrayList get(){

Given a binary tree, return the preorder traversal of its nodes' values. For example: Given binary tree{1,#,2,3}, 1 \ 2 / 3 return[1,2,3]. Note: Recursive solution

Determine whether an integer is a palindrome. Do this without extra space. click to show spoilers. Some hints: Could negative integers be palindromes? (ie, -1) If you are thinking of convertin

Given a roman numeral, convert it to an integer. Input is guaranteed to be within the range from 1 to 3999. 分析： 1~9: {"I", "II", "III", "IV", "V", "VI", "VII", "VIII", "IX"}; 10~90: {"X",