Added first commit of halfPlane

Author: Chillee

content/geometry/halfPlane.h

@@ -0,0 +1,50 @@
+
+/**
+ * Author:
+ * Date:
+ * License:
+ * Source:
+ * Description:
+ * Time:
+ * Status:
+ * Usage:
+ */
+#pragma once
+
+#include "Point.h"
+#include "sideOf.h"
+
+typedef Point<double> P;
+typedef array<P, 2> Line;
+#define v(a) (a[1] - a[0])
+#define c(a) (v(a).cross(a[0]))
+pair<int, P> lineInter(Line a, Line b) {
+	auto d = v(a).cross(v(b));
+	if (d == 0) return {-(c(a) == c(b)), P(0,0)};
+	else return {1, (v(b)*c(a) - v(a)*c(b))/d};
+}
+
+#define ang(a) atan2(v(a).y, v(a).x)
+int sideOf(Line l, P p) {return sideOf(l[0], l[1], p);}
+vector<P> halfPlaneIntersection(vector<Line> vs) {
+    sort(all(vs), [](auto a, auto b) { return ang(a) < ang(b);});
+    vs.resize(unique(all(vs), [](auto a, auto b){ return ang(a) == ang(b);}) - vs.begin());
+    deque<Line> deq({vs[0]});
+    deque<P> ans;
+    for (int i = 1; i < sz(vs); ++i) {
+        if (sgn(ang(vs[i]) - ang(vs[i-1])) == 0) continue;
+        while (sz(ans) && sideOf(vs[i], ans.back())< 0)
+            ans.pop_back(), deq.pop_back();
+        while(sz(ans) && sideOf(vs[i], ans.front()) < 0)
+            ans.pop_front(), deq.pop_front();
+        ans.push_back(lineInter(deq.back(), vs[i]).second);
+        deq.push_back(vs[i]);
+    }
+    while (sz(ans) && sideOf(deq.front(), ans.back()) < 0)
+        ans.pop_back(), deq.pop_back();
+    while (sz(ans) && sideOf(deq.back(), ans.front()) < 0)
+        ans.pop_front(), deq.pop_front();
+    if (sz(deq) <= 2) return {};
+    ans.push_back(lineInter(deq.front(), deq.back()).second);
+    return vector<P>(all(ans));
+}

fuzz-tests/geometry/PolygonCut.cpp

@@ -10,19 +10,11 @@ typedef long long ll;
 typedef pair<int, int> pii;
 typedef vector<int> vi;
 
-<<<<<<< HEAD:fuzz-tests/geometry/PolygonCut.cpp
 #include "../../content/geometry/PolygonArea.h"
 #include "../../content/geometry/PolygonCut.h"
 #include "../../content/geometry/sideOf.h"
 #include "../../content/geometry/insidePolygon.h"
 #include "../../content/geometry/SegmentIntersection.h"
-=======
-#include "../content/geometry/PolygonArea.h"
-#include "../content/geometry/PolygonCut.h"
-#include "../content/geometry/sideOf.h"
-#include "../content/geometry/insidePolygon.h"
-#include "../content/geometry/SegmentIntersection.h"
->>>>>>> Fixed broken dependency:fuzz-tests/polygon-cut.cpp
 
 typedef Point<double> P;
 int main() {