Calculate the number of vertices between i and j , j and k
if ( i < j ) : NEW_LINE INDENT x = j - i NEW_LINE DEDENT else : NEW_LINE INDENT x = j + n - i NEW_LINE DEDENT if ( j < k ) : NEW_LINE INDENT y = k - j NEW_LINE DEDENT else : NEW_LINE INDENT y = k + n - j NEW_LINE DEDENT