题解 | #整数与IP地址间的转换#

import java.util.*; public class Main { public static void main(String[] args) { Scanner scanner = new Scanner(System.in); while (scanner.hasNextLine()) { String ipStr = scanner.nextLine(); long ipLong = Long.parseLong(scanner.nextLine()); System.out.println(ipTranToInt(ipStr)); System.out.println(ipTranToString(ipLong)); } } public static long ipTranToInt(String ipStr) { long result = 0; String [] ipStrArray = ipStr.split("\."); for (String ip : ipStrArray) { result = (result << 8) + Integer.parseInt(ip); } return result; } public static String ipTranToString(long ipLong) { long ip = ipLong; long temp = 0; String result = ""; Stack stack = new Stack<>(); while (ip > 0) { temp = ip % (long)Math.pow(2, 8); stack.push(temp); ip = ip / (long)Math.pow(2, 8); } int c = 0; while (!stack.isEmpty()) { if (c == 0) { result = result + stack.pop(); c++; } else { result = result + "." + stack.pop(); } } return result; } }