Create triangles.cpp

Changes

1 changed files (+113/-0)

• 2016/December/Platinum/triangles.cpp (new)
  • @@ -0,0 +1,113 @@
    + #include <algorithm> + #include <iostream> + #include <fstream> + #include <cstring> + #include <vector> + #include <cmath> + using namespace std; + typedef long long ll; + typedef pair<int, int> ii; + typedef vector<int> vi; + typedef vector<ii> vii; + + struct point { + ll x, y; + point() { x = y = 0; } + point(ll _x, ll _y) : x(_x), y(_y) {} + bool operator < (point p) const { + return (x == p.x && y < p.y) || x < p.x; + } + bool operator == (point p) const { + return x == p.x && y == p.y; + } + } T[305]; + + struct vec { + ll x, y; + vec(ll _x, ll _y) : x(_x), y(_y) {} + }; + + vec to_vec(point a, point b) { + return vec(b.x - a.x, b.y - a.y); + } + + ll dot(vec a, vec b) { + return (a.x * b.x + a.y * b.y); + } + + ll norm_sq(vec v) { + return v.x * v.x + v.y * v.y; + } + + ll cross(vec a, vec b) { + return a.x * b.y - a.y * b.x; + } + + bool ccw(point p, point q, point r) { + return cross(to_vec(p, q), to_vec(p, r)) > 0; + } + + struct line { ll a, b, c; }; + + line to_line(point p1, point p2) { + return { p2.y - p1.y, p1.x - p2.x, p1.x * p2.y - p1.y * p2.x }; + } + + class fenwick_tree { + private: vector<int> FT; + public: + fenwick_tree(int N) { FT.assign(N + 1, 0); } + void update(int x, int val) { for (; x < FT.size(); x += x & -x) FT[x] += val; } + int query(int x) { int ret = 0; for (; x > 0; x -= x & -x) ret += FT[x]; return ret; } + int query(int x, int y) { return query(y) - (x == 1 ? 0 : query(x - 1)); } + }; + + int ans[305] = { 0 }; + + int main() { + ifstream cin("triangles.in"); + ofstream cout("triangles.out"); + + int N; + cin >> N; + for (int i = 0; i < N; i++) cin >> T[i].x >> T[i].y; + sort(T, T + N); + + for (int i = 0; i < N - 1; i++) { + for (int j = i + 1; j < N; j++) { + line L = to_line(T[i], T[j]); + + vector<pair<ii, point>> A, B; + for (int k = i + 1; k < N; k++) { + if (k != i && k != j) { + if (T[k].x * L.a + T[k].y * L.b < L.c) { + A.emplace_back(ii(k, k), T[k]); + } + } + } + + vector<ii> l, r; + int N = A.size(); + for (int i = 0; i < N; i++) { + l.emplace_back(A[i].first.first, i); + r.emplace_back(A[i].first.second, i); + } + sort(l.begin(), l.end(), [i](const ii& a, const ii& b) { return ccw(T[b.first], T[i], T[a.first]); }); + sort(r.begin(), r.end(), [j](const ii& a, const ii& b) { return ccw(T[a.first], T[j], T[b.first]); }); + for (int i = 0; i < N; i++) { + A[l[i].second].first.first = i + 1; + A[r[i].second].first.second = i + 1; + } + + sort(A.begin(), A.end()); + + fenwick_tree FT(N); + for (auto& p : A) { + ans[FT.query(p.first.second)]++; + FT.update(p.first.second, 1); + } + } + } + + for (int i = 0; i < N - 2; i++) cout << ans[i] << endl; + }