the set of points in the convex hull
a = [ ] NEW_LINE a . append ( [ 0 , 0 ] ) ; NEW_LINE a . append ( [ 3 , - 1 ] ) ; NEW_LINE a . append ( [ 4 , 5 ] ) ; NEW_LINE a . append ( [ - 1 , 4 ] ) ; NEW_LINE n = len ( a ) NEW_LINE p = [ 100 , 100 ] NEW_LINE addPoint ( a , p ) ; NEW_LINE