题解 | #验证IP地址#

import java.util.regex.Pattern;
class Solution {
  String chunkIPv4 = "([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])";
  Pattern pattenIPv4 =
          Pattern.compile("^(" + chunkIPv4 + "\\.){3}" + chunkIPv4 + "$");

  String chunkIPv6 = "([0-9a-fA-F]{1,4})";
  Pattern pattenIPv6 =
          Pattern.compile("^(" + chunkIPv6 + "\\:){7}" + chunkIPv6 + "$");

  public String solve(String IP) {
    if (IP.contains(".")) {
      return (pattenIPv4.matcher(IP).matches()) ? "IPv4" : "Neither";
    }
    else if (IP.contains(":")) {
      return (pattenIPv6.matcher(IP).matches()) ? "IPv6" : "Neither";
    }
    return "Neither";
  }
}