Segcolt/Codeforces-solutions
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Merge branch 'master' of https://git.puffypony.party/segcolt/codeforces-solutions

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Segcolt
2026-03-16 20:17:00 -03:00
parent 23630c1356 2d314df46f
commit ccd62bc6e9
18 changed files with 2123 additions and 245 deletions
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279
2019 China Collegiate Programming Contest Qinhuangdao Onsite/A. Angle Beats.cpp
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@@ -80,33 +80,31 @@ const ll OO = INT64_MAX >> 1;
struct pt {
ll x, y;
int c;
pt() = default;
pt(ll x, ll y): x(x), y(y) {}
pt(pt a, int c): x(a.x), y(a.y), c(c) {}
friend istream &operator >> (istream &is, pt &a) {
is >> a.x >> a.y;
return is;
}
pt operator - (pt b) {
return pt(x - b.x, y - b.y);
ll operator ^ (pt b) {
return x * b.y - y * b.x;
}
ll operator * (pt b) {
return x * b.x + y * b.y;
}
ll operator ^ (pt b) {
return x * b.y - y * b.x;
pt operator - (pt b) {
return pt(x - b.x, y - b.y);
}
};
int ccw(pt a, pt b, pt c)
{
ll r = (b - a) ^ (c - b);
ll r = (b - a) ^ (c - a);
return (r > 0) - (r < 0);
}
@@ -117,14 +115,26 @@ ll cdot(pt a, pt b, pt c)
int quad(pt a)
{
static int q[][2] = {{0, 1}, {3, 2}};
if (a.x == 0 && a.y > 0) {
return 0;
}
if (a.x > 0 && a.y == 0) {
return 1;
}
if (a.x == 0 && a.y < 0) {
return 2;
}
if (a.x < 0 && a.y == 0) {
return 3;
}
static const int q[][2] = {{0, 1}, {3, 2}};
return q[a.x < 0][a.y < 0];
}
bool polar_cmp(pt a, pt b)
{
if (quad(a) != quad(b)) {
return quad(a) < quad(b);
return quad(a) != quad(b);
}
return ccw(pt(0, 0), a, b) < 0;
}
@@ -140,202 +150,135 @@ void solve()
{
int n, q;
cin >> n >> q;
V<pt> pts(n + q);
cin >> pts;
vl ans(q);
vi inv(n);
vi va(q);
vi ev(n + q);
iota(all(inv), 0);
iota(all(va), n);
iota(all(ev), 0);
rep(i, n) {
auto cmp = [&](int j, int k) {
if (j == i) {
return false;
}
if (k == i) {
return true;
}
return polar_cmp(pts[j] - pts[i], pts[k] - pts[i]);
};
sort(all(va), cmp);
sort(all(inv), cmp);
int sz = inv.size() - 1;
V<pair<int, ll>> tmp;
vi p(n + q);
iota(all(p), 0);
auto cmpr = [&](vi &p, int i) {
if (p.empty()) {
return vector<pair<int, ll>>();
}
sort(all(p), [&](int j, int k){return polar_cmp(pts[j] - pts[i], pts[k] - pts[i]);});
V<pair<int, ll>> v;
int c = 1;
nrep(j, 1, sz) {
if (ccw(pts[i], pts[inv[j - 1]], pts[inv[j]]) == 0) {
nrep(j, 1, p.size()) {
if (ccw(pts[i], pts[p[j]], pts[p[j - 1]]) == 0) {
c++;
continue;
}
tmp.emplace_back(inv[j - 1], c);
v.emplace_back(p[j - 1], c);
c = 1;
}
v.emplace_back(p.back(), c);
return v;
};
tmp.emplace_back(inv.end()[-2], c);
vl ans(q);
int j = 0;
int k = 0;
rep(i, n) {
vvi qp(4);
nrep(j, n, n + q) {
qp[quad(pts[j] - pts[i])].push_back(j);
}
auto valid1 = [&]() {
auto p1 = pts[va[j]];
if (ccw(pts[i], p1, pts[inv[0]]) > 0 && ccw(pts[i], p1, pts[inv.end()[-2]]) > 0) {
return false;
vvi np(4);
rep(j, n) {
if (i == j) {
continue;
}
np[quad(pts[j] - pts[i])].push_back(j);
}
if (ccw(pts[i], p1, pts[inv[0]]) < 0 && ccw(pts[i], p1, pts[inv.end()[-2]]) < 0 &&
cdot(pts[i], p1, pts[inv[0]]) > 0 && cdot(pts[i], p1, pts[inv.end()[-2]]) > 0) {
return false;
}
return true;
V<V<pair<int, ll>>> cp = {cmpr(np[0], i), cmpr(np[1], i), cmpr(np[2], i), cmpr(np[3], i)};
auto cmp = [&](int j, int k) {
return polar_cmp(pts[j] - pts[i], pts[k] - pts[i]);
};
sort(all(qp[0]), cmp);
sort(all(qp[1]), cmp);
sort(all(qp[2]), cmp);
sort(all(qp[3]), cmp);
while (j < va.size()) {
auto p1 = pts[va[j]];
auto p2 = pts[tmp[k % tmp.size()].first];
if (!valid1()) {
j++;
continue;
}
if (ccw(pts[i], p1, p2) > 0) {
k++;
continue;
}
ll dot = cdot(pts[i], p1, p2);
if (dot < 0) {
j++;
continue;
}
if (dot > 0) {
auto p3 = pts[tmp[(k + 1) % tmp.size()].first];
if (ccw(pts[i], p1, p3) > 0 || cdot(pts[i], p1, p3) < 0) {
auto getcw = [&](vi &p, V<pair<int, ll>> &c) {
int j = 0;
int k = 0;
while (j < p.size() && k < c.size()) {
ll dot = cdot(pts[i], pts[p[j]], pts[c[k].first]);
if (dot == 0) {
ans[p[j] - n] += c[k].second;
j++;
continue;
}
k++;
continue;
if (dot > 0) {
k++;
continue;
}
j++;
}
ans[va[j] - n] += tmp[k % tmp.size()].second;
j++;
}
auto valid2 = [&]() {
auto p1 = pts[va[j]];
if (ccw(pts[i], p1, pts[inv[0]]) < 0 && ccw(pts[i], p1, pts[inv.end()[-2]]) < 0) {
return false;
}
if (ccw(pts[i], p1, pts[inv[0]]) > 0 && ccw(pts[i], p1, pts[inv.end()[-2]]) > 0 &&
cdot(pts[i], p1, pts[inv[0]]) > 0 && cdot(pts[i], p1, pts[inv.end()[-2]]) > 0) {
return false;
}
return true;
};
j = va.size() - 1;
k = tmp.size() - 1;
auto kpos = [&]() {
return (k % tmp.size() + tmp.size()) % tmp.size();
};
while (j >= 0) {
auto p1 = pts[va[j]];
auto p2 = pts[tmp[kpos()].first];
if (!valid2()) {
j--;
continue;
}
if (ccw(pts[i], p1, p2) < 0) {
k--;
continue;
}
ll dot = cdot(pts[i], p1, p2);
if (dot < 0) {
j--;
continue;
}
if (dot > 0) {
auto p3 = pts[tmp[((k - 1) % tmp.size() + tmp.size()) % tmp.size()].first];
if (ccw(pts[i], p1, p3) > 0 || cdot(pts[i], p1, p3) < 0) {
auto getccw = [&](vi &p, V<pair<int, ll>> &c) {
int j = (int)p.size() - 1;
int k = (int)c.size() - 1;
while (j >= 0 && k >= 0) {
ll dot = cdot(pts[i], pts[p[j]], pts[c[k].first]);
if (dot == 0) {
ans[p[j] - n] += c[k].second;
j--;
continue;
}
k--;
continue;
if (dot > 0) {
k--;
continue;
}
j--;
}
};
ans[va[j] - n] += tmp[kpos()].second;
j--;
rep(j, 4) {
getcw(qp[j], cp[(j + 1) % 4]);
getccw(qp[j], cp[((j - 1) % 4 + 4) % 4]);
}
}
nrep(i, n, n + q) {
auto cmp = [&](int j, int k) {
return polar_cmp(pts[j] - pts[i], pts[k] - pts[i]);
};
sort(all(inv), cmp);
V<pair<int, ll>> tmp;
int c = 1;
nrep(j, 1, n) {
if (ccw(pts[i], pts[inv[j - 1]], pts[inv[j]]) == 0) {
c++;
continue;
}
tmp.emplace_back(inv[j - 1], c);
c = 1;
vvi np(4);
rep(j, n) {
np[quad(pts[j] - pts[i])].push_back(j);
}
tmp.emplace_back(inv.end()[-1], c);
V<V<pair<int, ll>>> cp = {cmpr(np[0], i), cmpr(np[1], i), cmpr(np[2], i), cmpr(np[3], i)};
auto getcw = [&](V<pair<int, ll>> &p1, V<pair<int, ll>> &p2) {
int j = 0;
int k = 0;
while (j < p1.size() && k < p2.size()) {
ll dot = cdot(pts[i], pts[p1[j].first], pts[p2[k].first]);
if (dot == 0) {
ans[i - n] += p1[j].second * p2[k].second;
j++;
k++;
continue;
}
if (dot < 0) {
j++;
continue;
}
int j = 0;
int k = 0;
while (j < tmp.size()) {
while (k <= j) {
k++;
}
};
auto p1 = pts[tmp[j].first];
auto p2 = pts[tmp[k % tmp.size()].first];
ll dot = (p1 - pts[i]) * (p2 - pts[i]);
if (ccw(pts[i], p1, p2) >= 0 || dot < 0) {
j++;
continue;
}
if (dot > 0) {
k++;
continue;
}
ans[i - n] += tmp[j].second * tmp[k % tmp.size()].second;
j++;
rep(j, 4) {
getcw(cp[j], cp[(j + 1) % 4]);
}
}