string simplifyPath(string path) {

string result = "/";

deque<string> dQ;

for(int i = 0; i < path.length(); ) {

int pos = path.find('/', i);

string dir;

if(pos == string::npos) {

pos = path.length();

}

dir = path.substr(i, pos - i);

if(!dir.empty()) {

if(dir == ".") {

// nothing

} else if(dir == "..") {

if(!dQ.empty()) {

dQ.pop_back();

}

} else {

dQ.push_back(dir);

}

}

// skip all redundant slaces

for( ;pos < path.length() and path[pos] == '/'; ++pos);

i = pos;

}

while(!dQ.empty()) {

result += dQ.front();

dQ.pop_front();

if(!dQ.empty()) result += '/';

}

return result;

}