void removeRange(int left, int right) {
auto rng = rc.equal_range(make_pair(left, right));
int sv = right, ev = left;
if (rng.first != rc.end()) {
sv = rng.first->first;
if (rng.second != rc.begin()) {
auto pre = prev(rng.second);
ev = max(ev, pre->second);
}
}
rc.erase(rng.first, rng.second);
if (sv < left) { rc.insert(make_pair(sv, left)); }
if (right < ev) { rc.insert(make_pair(right, ev)); }
}
void addRange(int left, int right) {
auto rng = rc.equal_range(make_pair(left, right));
int nleft = left;
if (rng.first != rc.end()) { nleft = min(nleft, rng.first->first); }
if (rng.first != rc.begin()) {
auto pre = prev(rng.first);
if (pre != rc.end() && pre->second == left) {
nleft = pre->first;
rng.first = pre;
}
}
if (rng.second != rc.end() && rng.second->first == right) {
right = rng.second->second;
++rng.second;
} else if (rng.second != rc.begin()) {
auto pre = prev(rng.second);
if (pre != rc.end()) {
right = max(right, pre->second);
}
}
rc.erase(rng.first, rng.second);
rc.insert(make_pair(nleft, right));
}
