Problem 1632. Calculate the Number of Sign Changes in a Row Vector (No Element Is Zero)

For a row vector:

 V=[7 1 2 -3] 

there is one sign change (from 2 to -3). So, the function you write must return N=1.

For this row vector:

 V=[5 9 -2 7]; 

there are two sign changes, one from 9 to -2 and a second from -2 to 7, thus N=2.

Similarly

 V=[-4 -6 -7 -5 -6] and V=[3 7 6 5 6 7 8 7 6] 

have no sign changes (N=0).