int Trie::NextBranch(const Location& s1, const Location& s2){
int len1 = s1.length();
if (s1.at(0) == ODD_PREFIX){
char ch = s2.at(len1 - 1);
return ch & 0x0f;
}
else {
char ch = s2.at(len1);
return (ch >> 4) & 0x0f;
}
}
Location Trie::CommonPrefix(const Location& s1, const Location& s2){
Location out = "";
char pre = EVEN_PREFIX;
out.push_back(pre);
for (std::size_t i = 1; i < s1.length() && i < s2.length(); i++){
char c1 = s1.at(i);
char c2 = s2.at(i);
if ((c1 & 0xf0) != (c2 & 0xf0)){
break;
}
if (i == s1.length() - 1 && s1.at(0) == ODD_PREFIX){
char ch = c1 & 0xf0;
out.push_back(ch);
pre = ODD_PREFIX;
break;
}
if (i == s2.length() - 1 && s2.at(0) == ODD_PREFIX){
char ch = c1 & 0xf0;
out.push_back(ch);
pre = ODD_PREFIX;
break;
}
if ((c1 & 0x0f) != (c2 & 0x0f)){
char ch = c1 & 0xf0;
out.push_back(ch);
pre = ODD_PREFIX;
break;
}
char ch = c1;
out.push_back(ch);
}
out[0] = pre;
return out;
}