2、 public long getArea (Point p1, Point p2, Point p3, Point p4) { // write code here double ans = getTriangleArea(p1, p3, p2) + getTriangleArea(p4, p3, p1); long l = (long) ans; if (ans < l + 0.5) return l; return l + 1; } public double getTriangleArea(Point p1, Point p2, Point p3){ Point p12 = new Point(p2.x - p1.x, p2.y - p1.y); Point p13 = new Point(p3.x - p1.x, p3.y - p1.y); return Math.abs(p12.x * p13.y - p12.y * p13.x)/2.0; }