Check for the valid polyline with two segments
return ( x [ k ] == x [ i ] or x [ k ] == x [ j ] ) and isBetween ( y [ i ] , y [ j ] , y [ k ] ) or ( y [ k ] == y [ i ] or y [ k ] == y [ j ] ) and isBetween ( x [ i ] , x [ j ] , x [ k ] ) NEW_LINE def countLineSegments ( x , y ) : NEW_LINE