solved 12781

Author: atobaum

12000/12781/12781.cpp

@@ -0,0 +1,28 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+typedef long long ll;
+
+ll commutator(int x1, int y1, int x2, int y2){
+	return x1*y2-x2*y1;
+}
+
+ll ccw(int x1, int y1, int x2, int y2, int x3, int y3){
+	return commutator(x1, y1, x2, y2) + commutator(x2, y2, x3, y3) + commutator(x3, y3, x1, y1);
+}
+
+
+int main() {
+  ios::sync_with_stdio(false); cin.tie(NULL);
+
+  int x1, y1, x2, y2, x3, y3, x4, y4;
+
+  cin>>x1>>y1>>x2>>y2>>x3>>y3>>x4>>y4;
+
+  if(ccw(x1, y1, x2, y2, x3, y3) * ccw(x1, y1, x2, y2, x4, y4) < 0)
+	  cout << 1 << "\n";
+  else
+	  cout << 0 << "\n";
+
+  return 0;
+}