Advertisement
Not a member of Pastebin yet?
Sign Up,
it unlocks many cool features!
- // Short code and faster
- // Keeps upper hull for maximums.
- // add lines with -m and -b and return -ans to
- // make this code working for minimums.
- // source: http://codeforces.com/blog/entry/11155?#comment-162462
- const ll is_query = -(1LL<<62);
- struct Line {
- ll m, b;
- mutable function<const Line*()> succ;
- bool operator<(const Line& rhs) const {
- if (rhs.b != is_query) return m < rhs.m;
- const Line* s = succ();
- if (!s) return 0;
- ll x = rhs.m;
- return b - s->b < (s->m - m) * x;
- }
- };
- struct HullDynamic : public multiset<Line> {
- bool bad(iterator y) {
- auto z = next(y);
- if (y == begin()) {
- if (z == end()) return 0;
- return y->m == z->m && y->b <= z->b;
- }
- auto x = prev(y);
- if (z == end()) return y->m == x->m && y->b <= x->b;
- return 1.0 * (x->b - y->b)*(z->m - y->m) >= 1.0 * (y->b - z->b)*(y->m - x->m);
- }
- void insert_line(ll m, ll b) {
- auto y = insert({ m, b });
- y->succ = [=] { return next(y) == end() ? 0 : &*next(y); };
- if (bad(y)) { erase(y); return; }
- while (next(y) != end() && bad(next(y))) erase(next(y));
- while (y != begin() && bad(prev(y))) erase(prev(y));
- }
- ll eval(ll x) {
- auto l = *lower_bound((Line) { x, is_query });
- return l.m * x + l.b;
- }
- };
Advertisement
Add Comment
Please, Sign In to add comment
Advertisement