#include <bits/stdc++.h>
using namespace std;
using ll = int;
ll Bx, By;
struct Point {
ll x, y;
int idx;
inline Point operator-(const Point& p) const { return {x - p.x, y - p.y, idx}; }
inline Point operator+(const Point& p) const { return {x + p.x, y + p.y, idx}; }
inline long long cross(const Point& p) const {
return x * (long long)p.y - y * (long long)p.x;
}
inline bool operator<(const Point& p) const {
return to_upper().cross(p.to_upper()) > 0;
}
inline Point to_upper() const { return above() ? *this : negate(); }
inline bool above() const {
// TODO: Improve this
// const Point B{Bx, By, idx};
return Bx * (long long)y - By * (long long)x > 0;
// return B.cross(*this) > 0;
}
inline Point negate() const { return {-x, -y, idx}; }
};
short orientation(const Point& o, const Point& a, const Point& b) {
// assert((a - o).cross(b - o) != 0);
const long long x = (a - o).cross(b - o);
return (x > 0) - (x < 0);
}
short bit[30'001];
int bit_n = 30'001;
void clear(const int n) { memset(bit, 0, sizeof(short) * n); }
// TODO: Return should be int, not short.
int sum_single(int r) {
int ret = 0;
for (; r >= 0; r = (r & (r + 1)) - 1) ret += bit[r];
return ret;
}
int sum(int l, int r) { return sum_single(r) - sum_single(l - 1); }
void add(int idx, const short delta) {
for (; idx < bit_n; idx = idx | (idx + 1)) bit[idx] += delta;
}
unordered_map<int, vector<Point>> order_by_b;
bool cmp_by_b(const Point& p, const Point& q) {
const bool a1 = p.above();
const bool a2 = q.above();
if (a1 != a2) return a1;
return p.cross(q) > 0;
}
int handle_query(const vector<Point>& points1, const vector<Point>& points2,
const vector<Point>& ord_b, const Point& B) {
if (points1.empty() || points2.empty()) return 0;
bit_n = (int)points2.size();
clear(points2.size());
for (const auto& q : points2) {
if (!q.above()) {
add(q.idx, 1);
}
}
int total = 0;
int j = 0;
for (const Point& p : points1) {
while (j < (int)points2.size()) {
const Point& q = points2[j];
if (!(q < p)) break;
add(q.idx, q.above() ? 1 : -1);
j++;
}
Point from_point = p;
Point to_point = B + (p - B).negate();
if (!p.above()) swap(from_point, to_point);
// total += 1;
// continue;
const auto it1 = lower_bound(ord_b.begin(), ord_b.end(), from_point - B, cmp_by_b);
const auto it2 = lower_bound(ord_b.begin(), ord_b.end(), to_point - B, cmp_by_b);
const int from = it1 - ord_b.begin();
const int to = it2 - ord_b.begin();
total += sum(from, to - 1);
}
return total;
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int N, M, Q;
while (cin >> N >> M) {
vector<vector<Point>> tribe_points(M + 1);
for (int i = 0; i < N; i++) {
Point p;
int tribe;
cin >> p.x >> p.y >> tribe;
tribe_points[tribe].push_back(p);
}
Point A;
cin >> A.x >> A.y;
cin >> Bx >> By;
cin >> Q;
Bx -= A.x;
By -= A.y;
for (auto& points : tribe_points) {
for (auto& p : points) p = p - A;
}
const Point B{Bx, By, -1};
for (int m = 0; m <= M; m++) {
auto& points = tribe_points[m];
for (auto& p : tribe_points.at(m)) p = p - B;
sort(points.begin(), points.end(), cmp_by_b);
for (int i = 0; i < (int)points.size(); i++) {
points[i].idx = i;
}
order_by_b[m] = tribe_points.at(m);
for (auto& p : tribe_points.at(m)) p = p + B;
}
for (auto& points : tribe_points) {
sort(points.begin(), points.end());
}
const Point origin{0, 0, -1};
// TODO: Are the fenwick queries actually faster???? DO some experiments
// TODO: Set this value more properly, and explain that this doesn't really help
// but it's something. (assuming fenwick is ACTUALLY faster)
// TODO: Comment that this solution is probably not the intended one. The example
// solution is much faster (under a second).
// TODO: The thing is, I don't want to leave this code without the radial sweep, I
// want to add it for the lulz.
const int big_query = N / 2;
while (Q--) {
int i, j;
cin >> i >> j;
// cerr << tribe_points[i].size() * tribe_points[j].size() << endl;
const long long size = tribe_points[i].size() * tribe_points[j].size();
if (size > 100'000) {
// cerr << "big" << endl;
// cerr << tribe_points[j].size() << " > " << big_query << endl;
const int ans =
handle_query(tribe_points.at(i), tribe_points.at(j), order_by_b.at(j), B);
cout << ans << '\n';
} else {
int total = 0;
for (const Point& p : tribe_points[i]) {
for (const Point& q : tribe_points[j]) {
if (orientation(origin, B, p) == 1) {
if (orientation(B, p, q) == 1 && orientation(p, origin, q) == 1) total++;
} else {
if (orientation(origin, p, q) == 1 && orientation(p, B, q) == 1) total++;
}
}
}
cout << total << '\n';
}
}
t++;
}
}
Compilation message
dragon2.cpp: In function 'int main()':
dragon2.cpp:193:5: error: 't' was not declared in this scope
193 | t++;
| ^
dragon2.cpp:163:15: warning: unused variable 'big_query' [-Wunused-variable]
163 | const int big_query = N / 2;
| ^~~~~~~~~
