Check for the valid polyline with two segments
return ( x [ k ] == x [ i ] x [ k ] == x [ j ] ) && isBetween ( y [ i ] , y [ j ] , y [ k ] ) || ( y [ k ] == y [ i ] y [ k ] == y [ j ] ) && isBetween ( x [ i ] , x [ j ] , x [ k ] ) ; } int countLineSegments ( int x [ ] , int y [ ] ) {