力扣-字符串-468 检查ip

思路

考察字符串的使用，还有对所有边界条件的检查
spilt（“\.”），toCharArray，Integer.parseInt()

代码

class Solution {

    boolean checkIpv4Segment(String str){
        if(str.length() == 0 || str.length() > 4) return false;
        if(str.charAt(0) == '0' && str.length() > 1) return false;
        for(char c:str.toCharArray()){
            if(c < '0' || c > '9'){
                return false;
            }
        }
        int num = Integer.parseInt(str);
        if(num < 0 || num > 255) return false;
        return true;
    }

    boolean checkIpv6Segment(String str){
        for(char c:str.toCharArray()){
            if( (c < '0' ||  c > '9') && (c < 'a' || c > 'f') && (c < 'A' || c > 'F') ){
                return false;
            }
        }
        if(str.length() > 4 || str.length() == 0) return false;
        return true;
    }

    public String validIPAddress(String queryIP) {

        int dotLen = 0;
        int len = 0;
        for(int i = 0; i < queryIP.length(); i++){
            if(queryIP.charAt(i) == '.') dotLen++;
            else if(queryIP.charAt(i) == ':') len++;
        }

        if(dotLen == 3){
            String[] spilt = queryIP.split("\\.");
            if(spilt.length == 4){
                for(int i = 0; i < spilt.length; i++){
                    if(!checkIpv4Segment(spilt[i])){
                        return "Neither";
                    }
                }
                return "IPv4";
            }
        }
        if(len == 7){
            String[] spilt = queryIP.split(":");
            if(spilt.length == 8){
                for(int i = 0; i < spilt.length; i++){
                    if(!checkIpv6Segment(spilt[i])){
                        return "Neither";
                    }
                }
                return "IPv6";
            }
        }

        return "Neither";
    }
}