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10254.cpp
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10254.cpp
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#include <bits/stdc++.h>
#define vt vector
#define en '\n'
#define ll long long
#define ld long double
#define pb push_back
#define pii pair<int,int>
#define sz(x) (int)(x).size()
#define all(x) (x).begin(), (x).end()
#define rev(c) (c).rbegin(), (c).rend()
#define mid (st+end)/2
using namespace std;
const int INF = 0x3f3f3f3f; const int mINF = 0xc0c0c0c0;
const ll LINF = 0x3f3f3f3f3f3f3f3f; const ll mLINF = 0xc0c0c0c0c0c0c0c0;
int T = 1;
const double eps = 1e-12;
inline int diff(double lhs, double rhs) {
if (lhs - eps < rhs && rhs < lhs + eps) return 0;
return (lhs < rhs) ? -1 : 1;
}
struct Point {
// double x, y;
ll x,y;
bool operator==(const Point& rhs) const {
return diff(x, rhs.x) == 0 && diff(y, rhs.y) == 0;
}
Point operator+(const Point& rhs) const {
return Point{ x + rhs.x, y + rhs.y };
}
Point operator-(const Point& rhs) const {
return Point{ x - rhs.x, y - rhs.y };
}
// Point operator*(double t) const {
// return Point{ x * t, y * t };
// }
Point operator*(ll t) const {
return Point{ x * t, y * t };
}
};
inline double inner(const Point& a, const Point& b) {
return a.x * b.x + a.y * b.y;
}
inline double outer(const Point& a, const Point& b) {
return a.x * b.y - a.y * b.x;
}
inline double dist(const Point& a, const Point& b) {
return sqrt(inner(a - b, a - b));
}
inline int ccw(const Point& a, const Point& b, const Point& c) {
return diff(outer(b - a, c - a), 0);
}
// rotating calipers
void antipodal_pairs(vector<Point>& pt) {
// calculate convex hull
sort(pt.begin(), pt.end(), [](const Point& a, const Point& b) {
return (a.x == b.x) ? a.y < b.y : a.x < b.x;
});
vector<Point> up, lo;
for (const auto& p : pt) {
while (up.size() >= 2 && ccw(*++up.rbegin(), *up.rbegin(), p) >= 0) up.pop_back();
while (lo.size() >= 2 && ccw(*++lo.rbegin(), *lo.rbegin(), p) <= 0) lo.pop_back();
up.emplace_back(p);
lo.emplace_back(p);
}
double mx = mLINF;
Point p1, p2;
for (int i = 0, j = (int)lo.size() - 1; i + 1 < up.size() || j > 0; ) {
double d = dist(up[i], lo[j]);
if(d > mx) {
mx = d;
p1 = up[i];
p2 = lo[j];
}
if (i + 1 == up.size()) {
--j;
}
else if (j == 0) {
++i;
}
else if ((long long)(up[i + 1].y - up[i].y) * (lo[j].x - lo[j - 1].x)
> (long long)(up[i + 1].x - up[i].x) * (lo[j].y - lo[j - 1].y)) {
++i;
} else {
--j;
}
}
cout << p1.x << ' ' << p1.y << ' ' << p2.x << ' ' << p2.y << en;
}
void sol() {
int n;
cin >> n;
vt<Point> v(n);
for(auto& p : v) cin >> p.x >> p.y;
antipodal_pairs(v);
return;
}
int main() {
ios_base::sync_with_stdio(0); cin.tie(0);
cin >> T;
while(T--) {
sol();
}
return 0;
}