geo2d/circle_min

teapotd · Apr 1, 2024 · b78fbaa · b78fbaa
1 parent 0f970f3
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diff --git a/src/geo2d/circle_min.h b/src/geo2d/circle_min.h
@@ -0,0 +1,22 @@
+#pragma once
+#include "../template.h"
+#include "vector.h" // FLOATING_POINT_GEOMETRY
+#include "circle.h"
+
+mt19937 rnd(123);
+
+// Minimum circle enclosing a set of points.
+//! Source: https://github.com/kth-competitive-programming/kactl/blob/main/content/geometry/MinimumEnclosingCircle.h
+circle minDisk(vector<vec> p) { // time: O(n)
+	circle c;
+	shuffle(all(p), rnd);
+	rep(i, 0, sz(p)) if (c.side(p[i]) < 0) {
+		c = {p[i], 0};
+		rep(j, 0, i) if (c.side(p[j]) < 0) {
+			c = {(p[i]+p[j])/2,(p[i]-p[j]).len2()/4};
+			rep(k, 0, j) if (c.side(p[k]) < 0)
+				c = circum(p[i], p[j], p[k]);
+		}
+	}
+	return c;
+}
diff --git a/tests/README.md b/tests/README.md
@@ -3,6 +3,7 @@
 |                                    | deterministic | fuzz            | benchmark | yosupo               |
 |------------------------------------|:-------------:|:---------------:|:---------:|:--------------------:|
 | geo2d/circle                       | partial       | partial         |           |                      |
+| geo2d/circle                       |               |                 |           |                      |
 | geo2d/convex_hull                  |               | &check;         | &check;   |                      |
 | geo2d/halfplanes                   | &check;       | &check;         | &check;   |                      |
 | geo2d/line                         | &check;       |                 |           |                      |