CCW (CounterClockWise) is an algorithm for locating the relative position of two vectors using external entities. More specifically, it is a formula that determines the relative position of each vertex when there is a vector pointing to another vertex based on one vertex. If the vertex exists on the left side of a vector from one vertex to another vertex, the outer product has a positive value, and if it is on the right side, the outer product has a negative value. Finally, when three points are placed on one straight line, the outer product becomes zero. This can solve various geometric problems such as finding the area of a polygon, determining the position of a vertex (dividing inside / outside of a polygon), and drawing a convex polygon (Convex Hull).

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