Editorial's Solution is wrong! (unsigned long long int should not work but it is working--weak testcases)

#1

@anshumansingh the following editorial’s solution is wrong and every other solution that is using “unsigned long long int” is also wrong…

int Solution::compareVersion(string A, string B) {
    int i=0,j=0,m=A.length(),n=B.length();
    unsigned long long int val1=0,val2=0;
    while(i<m or j<n){
        val1=0,val2=0;
        while(i<A.length() and A[i]!='.'){
            val1=(val1*10)+(A[i++]-'0');
        }
        while(j<B.length() and B[j]!='.'){
            val2=(val2*10)+(B[j++]-'0');
        }
        if(j<n and B[j]=='.') ++j;
        if(i<m and A[i]=='.') ++i;
        if(val1>val2) return 1;
        else if(val1<val2) return -1;
    }
    return 0;
}

And test-case on which these are failing is :

18446744073709551614
18446744073709551620