\u9898\u76ee\u5927\u610f\uff1a\u7ed9\u4f60\u4e00\u4e2a\u5b57\u7b26\u4e32\uff0c\u8ba9\u4f60\u5224\u65ad\u662f\u5426\u662f\u5408\u6cd5\u7684ipv4\u6216\u8005ipv6\u5730\u5740\uff0c\u90fd\u4e0d\u5408\u6cd5\u8fd4\u56deNeighter.<\/p>\n
Write a function to check whether an input string is a valid IPv4 address or IPv6 address or neither.<\/p>\n
IPv4<\/b>\u00a0addresses are canonically represented in dot-decimal notation, which consists of four decimal numbers, each ranging from 0 to 255, separated by dots (“.”), e.g., Besides, leading zeros in the IPv4 is invalid. For example, the address\u00a0 IPv6<\/b>\u00a0addresses are represented as eight groups of four hexadecimal digits, each group representing 16 bits. The groups are separated by colons (“:”). For example, the address\u00a0 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,\u00a0 Besides, extra leading zeros in the IPv6 is also invalid. For example, the address\u00a0 Note:<\/b>\u00a0You may assume there is no extra space or special characters in the input string.<\/p>\n Example 1:<\/b><\/p>\n Example 2:<\/b><\/p>\n Example 3:<\/b><\/p>\n Solution 1: String \/ Brute force\u00a0<\/strong><\/p>\n <\/p>\n","protected":false},"excerpt":{"rendered":" \u9898\u76ee\u5927\u610f\uff1a\u7ed9\u4f60\u4e00\u4e2a\u5b57\u7b26\u4e32\uff0c\u8ba9\u4f60\u5224\u65ad\u662f\u5426\u662f\u5408\u6cd5\u7684ipv4\u6216\u8005ipv6\u5730\u5740\uff0c\u90fd\u4e0d\u5408\u6cd5\u8fd4\u56deNeighter. Write a function to check whether an input string is a valid IPv4 address or IPv6 address or neither. IPv4\u00a0addresses are canonically represented in…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[47],"tags":[177,224],"class_list":["post-1907","post","type-post","status-publish","format-standard","hentry","category-string","tag-medium","tag-regex","entry","simple"],"_links":{"self":[{"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/posts\/1907","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/comments?post=1907"}],"version-history":[{"count":2,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/posts\/1907\/revisions"}],"predecessor-version":[{"id":1909,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/posts\/1907\/revisions\/1909"}],"wp:attachment":[{"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/media?parent=1907"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/categories?post=1907"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/tags?post=1907"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}172.16.254.1<\/code>;<\/p>\n172.16.254.01<\/code>\u00a0is invalid.<\/p>\n2001:0db8:85a3:0000:0000:8a2e:0370:7334<\/code>\u00a0is 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\u00a02001:db8:85a3:0:0:8A2E:0370:7334<\/code>\u00a0is also a valid IPv6 address(Omit leading zeros and using upper cases).<\/p>\n2001:0db8:85a3::8A2E:0370:7334<\/code>\u00a0is an invalid IPv6 address.<\/p>\n02001:0db8:85a3:0000:0000:8a2e:0370:7334<\/code>\u00a0is invalid.<\/p>\nInput:<\/b> \"172.16.254.1\"\r\n\r\nOutput:<\/b> \"IPv4\"\r\n\r\nExplanation:<\/b> This is a valid IPv4 address, return \"IPv4\".\r\n<\/pre>\n
Input:<\/b> \"2001:0db8:85a3:0:0:8A2E:0370:7334\"\r\n\r\nOutput:<\/b> \"IPv6\"\r\n\r\nExplanation:<\/b> This is a valid IPv6 address, return \"IPv6\".\r\n<\/pre>\n
Input:<\/b> \"256.256.256.256\"\r\n\r\nOutput:<\/b> \"Neither\"\r\n\r\nExplanation:<\/b> This is neither a IPv4 address nor a IPv6 address.<\/pre>\n
\/\/ Author: Huahua\r\n\/\/ Running time: 4 ms\r\nclass Solution {\r\npublic:\r\n bool isV4Num(string n) {\r\n if (n.length() > 3 || n.empty()) return false;\r\n std::reverse(n.begin(), n.end());\r\n int a = 0; \r\n int f = 1;\r\n for (char c : n) {\r\n if (!isdigit(c)) return false;\r\n if (c == '0' && f > 1) return false;\r\n a += (c - '0') * f;\r\n f *= 10;\r\n }\r\n return a >= 0 && a <= 255;\r\n }\r\n \r\n bool isV6Num(string n) {\r\n if (n.length() > 4 || n.empty()) return false;\r\n std::reverse(n.begin(), n.end());\r\n \r\n int a = 0;\r\n int f = 1; \r\n for (char c : n) { \r\n if (isdigit(c)) \r\n a += (c - '0') * f;\r\n else if (c >= 'a' && c <= 'f' || c >= 'A' && c <= 'Z')\r\n a += (tolower(c) - 'a' + 10) * f;\r\n else\r\n return false;\r\n f *= 16;\r\n }\r\n \r\n return a >= 0 && a < (1 << 16);\r\n }\r\n \r\n string validIPAddress(string IP) {\r\n bool isIPv4 = true;\r\n bool isIPv6 = true;\r\n string cur;\r\n int seg = 0;\r\n for (char c: IP) {\r\n if (c == '.') { ++seg; isIPv6 = false; isIPv4 &= isV4Num(cur); cur.clear(); }\r\n else if (c == ':') { ++seg; isIPv4 = false; isIPv6 &= isV6Num(cur); cur.clear(); }\r\n else cur += c;\r\n }\r\n isIPv4 &= isV4Num(cur) && seg == 3;\r\n isIPv6 &= isV6Num(cur) && seg == 7;\r\n \r\n return isIPv4 ? \"IPv4\" : (isIPv6 ? \"IPv6\" : \"Neither\");\r\n }\r\n};<\/pre>\n