1 class Solution {
 2     func validIPAddress(_ IP: String) -> String {
 3         if isValidIPv4(IP) {return "IPv4"}
 4         else if isValidIPv6(IP) {return "IPv6"}
 5         else
 6         {
 7             return "Neither"
 8         }
 9     }
10
11     func isValidIPv4(_ ip:String) -> Bool
12     {
13         if ip.count < 7 {return false}
14         if ip[0] == "." {return false}
15         if ip[ip.count-1] == "." {return false}
16         var tokens:[String] = ip.components(separatedBy:".")
17         if tokens.count != 4  {return false}
18         for token in tokens
19         {
20             if !isValidIPv4Token(token) {return false}
21         }
22         return true
23     }
24
25     func isValidIPv4Token(_ token:String) -> Bool
26     {
27         if token.hasPrefix("0") && token.count > 1 {return false}
28
29         if let parsedInt = Int(token)
30         {
31             if parsedInt < 0 || parsedInt > 255 {return false}
32             if parsedInt==0 && token[0] != "0" {return false}
33             return true
34         }
35         else
36         {
37             return false
38         }
39     }
40
41     func isValidIPv6(_ ip:String) -> Bool
42     {
43         if ip.count < 15 {return false}
44         if ip[0] == ":" {return false}
45         if ip[ip.count-1] == ":" {return false}
46         var tokens:[String] = ip.components(separatedBy:":")
47         if tokens.count != 8  {return false}
48         for token in tokens
49         {
50             if !isValidIPv6Token(token) {return false}
51         }
52         return true
53     }
54
55         func isValidIPv6Token(_ token:String) -> Bool
56     {
57         if token.count == 0 || token.count > 4 {return false}
58         for c in token.characters
59         {
60             var isDigit:Bool = c.ascii >= 48 && c.ascii <= 57
61             var isUppercaseAF:Bool = c.ascii >= 65 && c.ascii <= 70
62             var isLowerCaseAF:Bool = c.ascii >= 97 && c.ascii <= 102
63             if !(isDigit || isUppercaseAF || isLowerCaseAF)
64             {
65                 return false
66             }
67         }
68         return true
69     }
70 }
71
72 extension String {
73     //subscript函数可以检索数组中的值
74     //直接按照索引方式截取指定索引的字符
75     subscript (_ i: Int) -> Character {
76         //读取字符
77         get {return self[index(startIndex, offsetBy: i)]}
78     }
79 }
80
81 extension Character
82 {
83   //属性：ASCII整数值(定义小写为整数值)
84    var ascii: Int {
85         get {
86             let s = String(self).unicodeScalars
87             return Int(s[s.startIndex].value)
88         }
89     }
90 }

 1 class Solution {
 2     func validIPAddress(_ IP: String) -> String {
 3
 4         let ipv4 = IP.components(separatedBy: ".")
 5
 6         if ipv4.count == 4 {
 7
 8             return validIPv4Adress(ipv4)
 9         }
10
11         let ipv6 = IP.components(separatedBy: ":")
12
13         if ipv6.count == 8 {
14
15             return validIPv6Adress(ipv6)
16         }
17
18         return "Neither"
19     }
20
21     /// IP v4 检验
22     private func validIPv4Adress(_ ips: [String]) -> String{
23
24         for ip in ips {
25
26             if !ip.isValidIPv4() {
27                 return "Neither"
28             }
29         }
30
31         return "IPv4"
32     }
33
34
35     /// IP v6 检验
36     private func validIPv6Adress(_ ips: [String]) -> String{
37
38         for ip in ips {
39
40             if !ip.isValidIPv6() {
41                 return "Neither"
42             }
43         }
44
45         return "IPv6"
46     }
47 }
48
49 extension String{
50
51     func isValidIPv4() -> Bool{
52
53         /// 不可前缀 0
54         if self.count > 1 && self.hasPrefix("0") { return false }
55
56         guard let ip = UInt(self) else { return false }
57
58         if ip == 0 && self.contains("-") { return false }
59
60         return ip <= 255
61     }
62
63     func isValidIPv6() -> Bool{
64
65         if self.count > 4 { return false }
66
67         guard let ip = UInt(self, radix: 16) else { return false }
68
69         if ip == 0 && self.contains("-") { return false }
70
71         return true
72     }
73 }