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LeetCode-468-Validate-IP-Address.java
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LeetCode-468-Validate-IP-Address.java
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class Solution {
// 1. Write a IP Parser
/*
Runtime: 1 ms, faster than 98.57% of Java online submissions for Validate IP Address.
Memory Usage: 34.7 MB, less than 100.00% of Java online submissions for Validate IP Address.
*/
public String validIPAddress(String IP) {
if (IP.startsWith(".") || IP.endsWith(".") || IP.startsWith(":") || IP.endsWith(":")) return "Neither";
boolean isIPv4 = true;
String[] strs;
if (IP.contains(":")) {
strs = IP.split("\\:");
isIPv4 = false;
} else if (IP.contains(".")) {
strs = IP.split("\\.");
} else {
return "Neither";
}
// System.out.println("isIPv4: " + isIPv4 + " strs: " + Arrays.toString(strs));
if (isIPv4 && strs.length != 4) {
return "Neither";
} else if (!isIPv4 && strs.length != 8) {
return "Neither";
}
for (String s : strs) {
if (isIPv4) {
if (!isValidIPv4(s)) return "Neither";
} else {
if (!isValidIPv6(s)) return "Neither";
}
}
return isIPv4 ? "IPv4" : "IPv6";
}
private boolean isValidIPv4(String s) {
if (s == null || s.length() == 0 || s.length() > 3) return false;
int num = 0;
for (int i = 0; i < s.length(); i++) {
char c = s.charAt(i);
if (i == 0 && c == '0') return s.equals("0");
if (c < '0' || c > '9') return false;
num = 10 * num + c - '0';
}
return num >= 0 && num <= 255;
}
private boolean isValidIPv6(String s) {
if (s == null || s.length() == 0 || s.length() > 4) return false;
for (char c : s.toCharArray()) {
if (!(c >= '0' && c <= '9') && !(c >= 'A' && c <= 'F') && !(c >= 'a' && c <= 'f')) {
return false;
}
}
return true;
}
// 2. Write RegExpression
/*
https://leetcode.com/problems/validate-ip-address/discuss/95504/Java-Simple-Solution-with-RegExp
Runtime: 6 ms, faster than 8.25% of Java online submissions for Validate IP Address.
Memory Usage: 36.2 MB, less than 100.00% of Java online submissions for Validate IP Address.
*/
// public String validIPAddress(String IP) {
// if(IP.matches("(([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])\\.){3}([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])"))return "IPv4";
// if(IP.matches("(([0-9a-fA-F]{1,4}):){7}([0-9a-fA-F]{1,4})"))return "IPv6";
// return "Neither";
// }
}