题目：

题解：

class Solution {public String validIPAddress(String queryIP) {if (queryIP.indexOf('.') >= 0) {// IPv4int last = -1;for (int i = 0; i < 4; ++i) {int cur = (i == 3 ? queryIP.length() : queryIP.indexOf('.', last + 1));if (cur < 0) {return "Neither";}if (cur - last - 1 < 1 || cur - last - 1 > 3) {return "Neither";}int addr = 0;for (int j = last + 1; j < cur; ++j) {if (!Character.isDigit(queryIP.charAt(j))) {return "Neither";}addr = addr * 10 + (queryIP.charAt(j) - '0');}if (addr > 255) {return "Neither";}if (addr > 0 && queryIP.charAt(last + 1) == '0') {return "Neither";}if (addr == 0 && cur - last - 1 > 1) {return "Neither";}last = cur;}return "IPv4";} else {// IPv6int last = -1;for (int i = 0; i < 8; ++i) {int cur = (i == 7 ? queryIP.length() : queryIP.indexOf(':', last + 1));if (cur < 0) {return "Neither";}if (cur - last - 1 < 1 || cur - last - 1 > 4) {return "Neither";}for (int j = last + 1; j < cur; ++j) {if (!Character.isDigit(queryIP.charAt(j)) && !('a' <= Character.toLowerCase(queryIP.charAt(j)) && Character.toLowerCase(queryIP.charAt(j)) <= 'f')) {return "Neither";}}last = cur;}return "IPv6";}}
}