diff options
Diffstat (limited to 'content/datastructures/dynamicConvexHull.cpp')
| -rw-r--r-- | content/datastructures/dynamicConvexHull.cpp | 18 |
1 files changed, 9 insertions, 9 deletions
diff --git a/content/datastructures/dynamicConvexHull.cpp b/content/datastructures/dynamicConvexHull.cpp index 2bd67a6..7148e31 100644 --- a/content/datastructures/dynamicConvexHull.cpp +++ b/content/datastructures/dynamicConvexHull.cpp @@ -1,22 +1,22 @@ struct Line { - mutable ll m, b, p; + mutable ll m, c, p; bool operator<(const Line& o) const {return m < o.m;} bool operator<(ll x) const {return p < x;} }; -struct HullDynamic : multiset<Line, less<>> { - // (for doubles, use inf = 1/.0, div(a,b) = a/b) - ll div(ll a, ll b) {return a / b - ((a ^ b) < 0 && a % b);} +struct HullDynamic : multiset<Line, less<>> { // max über Geraden + // (for doubles, use INF = 1/.0, div(a,c) = a/c) + ll div(ll a, ll c) {return a / c - ((a ^ c) < 0 && a % c);} bool isect(iterator x, iterator y) { if (y == end()) {x->p = INF; return false;} - if (x->m == y->m) x->p = x->b > y->b ? INF : -INF; - else x->p = div(y->b - x->b, x->m - y->m); + if (x->m == y->m) x->p = x->c > y->c ? INF : -INF; + else x->p = div(y->c - x->c, x->m - y->m); return x->p >= y->p; } - void add(ll m, ll b) { - auto x = insert({m, b, 0}); + void add(ll m, ll c) { + auto x = insert({m, c, 0}); while (isect(x, next(x))) erase(next(x)); if (x != begin()) { --x; @@ -29,6 +29,6 @@ struct HullDynamic : multiset<Line, less<>> { ll query(ll x) { auto l = *lower_bound(x); - return l.m * x + l.b; + return l.m * x + l.c; } }; |