468. 验证IP地址(模拟)

​​468. 验证IP地址​​(模拟)

分类模拟。

写的好丑。

class Solution {
public:
    bool isnumber(string s){
       // cout<
        if(s.size()>3) return false;
        for(auto ch:s) if(!isdigit(ch)) return false;
        int x = stoi(s);
       // printf("x=%d\n",x);
        int len = 0;
        int y = x;
        while(y>0){
            y/=10;
            len++;
        }
        if(!x) len = 1;
        if(len==s.size() && x>=0&&x<=255) return true;
        return false;
    }
    bool myalpha(char ch){
        return (ch>='a'&&ch<='f') || (ch>='A'&&ch<='F');
    }
    bool isnumber1(string s){
      //  cout<
        int ls = (int)s.size();
        if(ls<1 ||ls >4) return false;
        for(auto ch:s) if(!isdigit(ch) && !myalpha(ch)) return false;
        return true;
    }
    bool f1(string s){
        int c = 0;
        vector<int>a;
        for(int i=0;i<s.size();i++){
            if(s[i]=='.') a.push_back(i),c++;
        }
        if(c!=3) return false;
        int l = 0;
        a.push_back((int)s.size());
        //printf("c=%d\n",c);
        for(int i=0;i<4;i++){
            
            int r = a[i]-1;
            //printf("(%d,%d)\n",l,r);
            if(l<=r && isnumber(s.substr(l,r-l+1))){
                ;
            }
            else return false;
            l = a[i]+1;
        }
        return true;
    }   
    bool f2(string s){
         int c = 0;
        vector<int>a;
        for(int i=0;i<s.size();i++){
            if(s[i]==':') a.push_back(i),c++;
        }
        if(c!=7) return false;   
        int l = 0;
        a.push_back((int)s.size());
        //printf("c=%d\n",c);
        for(int i=0;i<8;i++){
            
            int r = a[i]-1;
            //printf("(%d,%d)\n",l,r);
            if(l<=r && isnumber1(s.substr(l,r-l+1))){
                ;
            }
            else return false;
            l = a[i]+1;
        }
        return true;    
    }
    string validIPAddress(string s) {
        if(f1(s)) return "IPv4";
        else if(f2(s)) return "IPv6";
        else return "Neither";
    }
};