LeetCode-468. Validate IP Address

LeetCode-468. Validate IP Address

​​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.

题解：超级垃圾的一道题目......到处设坑有啥意思，我提交的时候74赞421踩，反正我踩了一脚。

class Solution {public: string validIPAddress(string IP) { if (is_ipv4(IP) == true){ return "IPv4"; } else if (is_ipv6(IP) == true){ return "IPv6"; } else { return "Neither"; } } int str_to_int(string s){ int ans = 0; for (int i = 0; i < s.length(); i++){ ans += s[i] - 48; ans *= 10; } ans /= 10; return ans; } bool is_ipv4(string s){ vector v; string idx = ""; for (int i = 0; i < s.length(); i++){ if (s[i] != '.'){ idx += s[i]; } else if (s[i] == '.'){ v.push_back(idx); idx.clear(); } } v.push_back(idx); if (v.size() != 4){ return false; } for (int i = 0; i < 4; i++){ int l = v[i].length(); if (l <= 0 || l > 3){ return false; } if (l > 1 && v[i][0] == '0'){ return false; } if (str_to_int(v[i]) < 0 || str_to_int(v[i]) > 255){ return false; } } return true; } bool is_ipv6(string s){ vector v; string idx = ""; for (int i = 0; i < s.length(); i++){ if (s[i] != ':'){ idx += s[i]; } else if (s[i] == ':'){ v.push_back(idx); idx.clear(); } } v.push_back(idx); if (v.size() != 8){ return false; } for (int i = 0; i < 8; i++){ int l = v[i].length(); if (l > 4 || l == 0){ return false; } else{ for (int j = 0; j < l; j++){ if (v[i][j] < '0' || (v[i][j] > '9' && v[i][j] <'A') || (v[i][j] > 'F' && v[i][j] < 'a') || v[i][j] > 'f'){ return false; } } } } return true; }};

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