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Write a function to check whether an input string is a valid IPv4 address or IPv6 address or neither.

IPv4?addresses are canonically represented in dot-decimal notation, which consists of four decimal numbers, each ranging from 0 to 255, separated by dots ("."), e.g.,172.16.254.1;

Besides, leading zeros in the IPv4 is invalid. For example, the address?172.16.254.01?is invalid.

IPv6?addresses are represented as eight groups of four hexadecimal digits, each group representing 16 bits. The groups are separated by colons (":"). For example, the address?2001:0db8:85a3:0000:0000:8a2e:0370:7334?is a valid one. Also, we could omit some leading zeros among four hexadecimal digits and some low-case characters in the address to upper-case ones, so?2001:db8:85a3:0:0:8A2E:0370:7334?is also a valid IPv6 address(Omit leading zeros and using upper cases).

However, we don't replace a consecutive group of zero value with a single empty group using two consecutive colons (::) to pursue simplicity. For example,?2001:0db8:85a3::8A2E:0370:7334?is an invalid IPv6 address.

Besides, extra leading zeros in the IPv6 is also invalid. For example, the address?02001:0db8:85a3:0000:0000:8a2e:0370:7334?is invalid.

Note:?You may assume there is no extra space or special characters in the input string.

Example 1:

Input: "172.16.254.1"Output: "IPv4"Explanation: This is a valid IPv4 address, return "IPv4".?

Example 2:

Input: "2001:0db8:85a3:0:0:8A2E:0370:7334"Output: "IPv6"Explanation: This is a valid IPv6 address, return "IPv6".?

Example 3:

Input: "256.256.256.256"Output: "Neither"Explanation: This is neither a IPv4 address nor a IPv6 address.

---

編寫一個函數來驗證輸入的字符串是否是有效的 IPv4 或?IPv6 地址。

IPv4?地址由十進制數和點來表示，每個地址包含4個十進制數，其范圍為?0 -?255，?用(".")分割。比如，172.16.254.1；

同時，IPv4 地址內的數不會以 0 開頭。比如，地址?172.16.254.01?是不合法的。

IPv6?地址由8組16進制的數字來表示，每組表示?16 比特。這些組數字通過 (":")分割。比如,??2001:0db8:85a3:0000:0000:8a2e:0370:7334?是一個有效的地址。而且，我們可以加入一些以 0 開頭的數字，字母可以使用大寫，也可以是小寫。所以，?2001:db8:85a3:0:0:8A2E:0370:7334?也是一個有效的 IPv6 address地址 (即，忽略 0 開頭，忽略大小寫)。

然而，我們不能因為某個組的值為 0，而使用一個空的組，以至于出現 (::) 的情況。?比如，?2001:0db8:85a3::8A2E:0370:7334是無效的 IPv6 地址。

同時，在 IPv6 地址中，多余的 0 也是不被允許的。比如，?02001:0db8:85a3:0000:0000:8a2e:0370:7334?是無效的。

說明:?你可以認為給定的字符串里沒有空格或者其他特殊字符。

示例 1:

輸入: "172.16.254.1"輸出: "IPv4"解釋: 這是一個有效的 IPv4 地址, 所以返回 "IPv4"。

示例 2:

輸入: "2001:0db8:85a3:0:0:8A2E:0370:7334"輸出: "IPv6"解釋: 這是一個有效的 IPv6 地址, 所以返回 "IPv6"。

示例 3:

輸入: "256.256.256.256"輸出: "Neither"解釋: 這個地址既不是 IPv4 也不是 IPv6 地址。

---

12ms 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函數可以檢索數組中的值 74 //直接按照索引方式截取指定索引的字符 75 subscript (_ i: Int) -> Character { 76 //讀取字符 77 get {return self[index(startIndex, offsetBy: i)]} 78 } 79 } 80 81 extension Character 82 { 83 //屬性：ASCII整數值(定義小寫為整數值) 84 var ascii: Int { 85 get { 86 let s = String(self).unicodeScalars 87 return Int(s[s.startIndex].value) 88 } 89 } 90 }

---

12ms

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 檢驗 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 檢驗 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 /// 不可前綴 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 }

?

轉載于:https://www.cnblogs.com/strengthen/p/10346244.html

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