264 lines
5.6 KiB
C++

/* Problem URL: https://codeforces.com/gym/104871/problem/G */
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
template <class T, class comp = less<>>
using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
#define V vector
#define rmin(a, b) a = min(a, b)
#define rmax(a, b) a = max(a, b)
#define rep(i, lim) for (int i = 0; i < (lim); i++)
#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
#define repv(i, v) for (auto &i : (v))
#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
#define sortv(v) sort(v.begin(), v.end())
#define all(v) (v).begin(), (v).end()
using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using vvvvi = vector<vvvi>;
using ll = long long;
using vl = vector<ll>;
using vvl = vector<vl>;
using vvvl = vector<vvl>;
using vvvvl = vector<vvvl>;
template<class v>
auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
os << vec[0];
for (size_t i = 1; i < vec.size(); i++) {
os << ' ' << vec[i];
}
os << '\n';
return os;
}
template<class v>
auto operator>>(istream &is, vector<v> &vec)->istream& {
for (auto &i : vec) {
is >> i;
}
return is;
}
template<class v>
auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
for (auto &i : vec) {
os << i[0];
for (size_t j = 1; j < i.size(); j++) {
os << ' ' << i[j];
}
os << '\n';
}
return os;
}
template<class v>
auto operator>>(istream &is, vector<vector<v>> &vec)->istream& {
for (auto &i : vec) {
for (auto &j : i) {
is >> j;
}
}
return is;
}
using ld = long double;
ld EPS = 1e-16L;
bool eq(ld a, ld b) {
return abs(a - b) <= EPS;
}
struct pt {
ld x, y;
pt(ld x = 0, ld y = 0): x(x), y(y) {}
ld operator^(const pt p) const {
return x*p.y - y*p.x;
}
pt operator-(const pt p) const {
return {x - p.x, y - p.y};
}
ld operator*(const pt p) const {
return x*p.x + y*p.y;
}
friend istream& operator >> (istream& in, pt &p) {
return in >> p.x >> p.y;
}
};
ld dist(pt p, pt q)
{
return hypot(p.y - q.y, p.x - q.x);
}
ld sarea(pt p, pt q, pt r)
{
return ((q-p)^(r-q)) / 2;
}
struct line {
pt p, q;
line() {}
line (pt p, pt q): p(p), q(q) {}
};
bool ccw(pt p, pt q, pt r)
{
return sarea(p, q, r) > EPS;
}
ld disttoline(pt p, line r)
{
return 2 * abs(sarea(p, r.p, r.q)) / dist(r.p, r.q);
}
bool isinseg(pt p, line r)
{
pt a = r.p - p, b = r.q - p;
return eq((a^b), 0) and (a * b) < EPS;
}
bool interseg(line r, line s)
{
if (isinseg(r.p, s) or isinseg(r.q, s) or isinseg(s.p, r) or isinseg(s.q, r)) {
return true;
}
return ccw(r.p, r.q, s.p) != ccw(r.p, r.q, s.q) and ccw(s.p, s.q, r.p) != ccw(s.p, s.q, r.q);
}
ld disttoseg(pt p, line r)
{
if ((r.q - r.p) * (p - r.p) < 0) {
return dist(r.p, p);
}
if ((r.p - r.q) * (p - r.q) < 0) {
return dist(r.q, p);
}
return disttoline(p, r);
}
int main()
{
ios::sync_with_stdio(false);
cin.tie(nullptr);
int t;
cin >> t;
while (t--) {
pt a, b;
pt cir;
ld r;
cin >> a >> b >> cir >> r;
if (eq(a.x, b.x) && eq(a.y, b.y)) {
ld dista = dist(a, cir);
if (dista <= r) {
cout << "0\n";
continue;
}
dista -= r;
cout << setprecision(12) << (dista - r) * 2 << '\n';
continue;
}
ld distret = disttoseg(cir, line(a, b));
cout << distret << '\n';
if (distret <= r) {
cout << setprecision(12) << dist(a, b) << '\n';
continue;
}
a.x -= cir.x;
a.y -= cir.y;
b.x -= cir.x;
b.y -= cir.y;
ld low = -r;
ld high = r;
ld ans = 1e18;
ld eps = 1e-9;
while (high - low >= eps) {
ld third = (high - low) / 3;
ld mid1 = low + third;
ld mid2 = high - third;
auto getans = [&](ld mid) {
ld one = (a.x - mid);
ld two = (a.y - sqrt(r * r - mid * mid));
ld ac = sqrt(one * one + two * two);
one = (b.x - mid);
two = (b.y - sqrt(r * r - mid * mid));
ac += sqrt(one * one + two * two);
return ac;
};
ld ans1 = getans(mid1);
ld ans2 = getans(mid2);
if (ans1 <= ans2) {
high = mid2;
ans = ans1;
continue;
}
low = mid1;
ans = ans2;
}
low = -r;
high = r;
while (high - low >= eps) {
ld third = (high - low) / 3;
ld mid1 = low + third;
ld mid2 = high - third;
auto getans = [&](ld mid) {
ld one = (a.x - mid);
ld two = (a.y + sqrt(r * r - mid * mid));
ld ac = sqrt(one * one + two * two);
one = (b.x - mid);
two = (b.y + sqrt(r * r - mid * mid));
ac += sqrt(one * one + two * two);
return ac;
};
ld ans1 = getans(mid1);
ld ans2 = getans(mid2);
if (ans1 <= ans2) {
high = mid2;
ans = ans1;
continue;
}
low = mid1;
ans = ans2;
}
cout << setprecision(12) << ans << '\n';
}
}