def polar_angle(p0, point_list):
'''sort a sequence <p1, p2, ... , pn> of n points according to
their polar angles with respect to a given origin point p0.
'''
v0 = vector((p0[0] + 1, p0[1]), p0) # The polar angle of v0 is 0
vector_list = [vector(p, p0) for p in point_list]
angle_0 = [] #list of vectors whose polar angles are 0
angle_pi = [] #list of vectors whose polar angles are pi
angle_0_pi = [] #list of vectors whose polar angles are larger than 0 and smaller than pi
angle_pi_2pi = [] #list of vectors whose polar angles are larger than pi and smaller than 2pi
for v in vector_list:
if v == v0:
if v.x > 0:
angle_0.append(v)
elif v.x < 0:
angle_pi.append(v)
elif v < v0:
angle_pi_2pi.append(v)
elif v > v0:
angle_0_pi.append(v)
heap_0_pi = max_heap(angle_0_pi)
heap_pi_2pi = max_heap(angle_pi_2pi)
heap_0_pi.heapsort()
heap_pi_2pi.heapsort()
return [(v.x, v.y) for v in (angle_0 + heap_0_pi + angle_pi + heap_pi_2pi)]
def polar_angle(p0, point_list):
'''sort a sequence <p1, p2, ... , pn> of n points according to
their polar angles with respect to a given origin point p0.
'''
v0 = vector((p0[0] + 1, p0[1]), p0) # The polar angle of v0 is 0
vector_list = [vector(p, p0) for p in point_list]
angle_0 = [] #list of vectors whose polar angles are 0
angle_pi = [] #list of vectors whose polar angles are pi
angle_0_pi = [
] #list of vectors whose polar angles are larger than 0 and smaller than pi
angle_pi_2pi = [
] #list of vectors whose polar angles are larger than pi and smaller than 2pi
for v in vector_list:
if v == v0:
if v.x > 0:
angle_0.append(v)
elif v.x < 0:
angle_pi.append(v)
elif v < v0:
angle_pi_2pi.append(v)
elif v > v0:
angle_0_pi.append(v)
heap_0_pi = max_heap(angle_0_pi)
heap_pi_2pi = max_heap(angle_pi_2pi)
heap_0_pi.heapsort()
heap_pi_2pi.heapsort()
return [(v.x, v.y) for v in (angle_0 + heap_0_pi + angle_pi + heap_pi_2pi)]
def any_disks_intersect(S):
'''This algorithm takes as input a set S of n disks represented by its center point and radius, returning the boolean value TRUE if any pair of disks in S intersects, and FALSE otherwise.'''
T = rb_tree()
point_list = []
disk_list = []
for s in S:
disk_list.append(disk(s))
for s in disk_list:
center_point = s[0]
radius = s[1]
x = center_point[0]
y = center_point[1]
point_list.append(point([x - radius, 0, y], s))
point_list.append(point([x + radius, 1, y], s))
heap_point = max_heap(point_list)
heap_point.heapsort()
print heap_point
for p in heap_point:
if p[1] == 0:
s = p.disk
T.insert(s)
a = T.above(s)
b = T.below(s)
print "insert: ", a, b
if (a != None and disks_intersect(a, s)) or (b != None and disks_intersect(b, s)):
return True
if p[1] == 1:
s = p.disk
a = T.above(s)
b = T.below(s)
if a != None and b != None and disks_intersect(a, b):
return True
T.delete(s)
return False
def any_segments_intersect(S):
'''This algorithm takes as input a set S of n line segments, returning the boolean value TRUE if any pair of segments in S intersects, and FALSE otherwise.'''
T = rb_tree()
segment_list = []
point_list = []
for s in S:
segment_list.append(segment(s))
for s in segment_list:
point_list.append(point([s[0][0], 0, s[0][1]], s))
point_list.append(point([s[1][0], 1, s[1][1]], s))
heap_point = max_heap(point_list)
heap_point.heapsort()
for p in heap_point:
if p[1] == 0:
s = p.segment
T.insert(s)
a = T.above(s)
b = T.below(s)
if (a != None and segments_intersect(a[0], a[1], s[0], s[1])) or (b != None and segments_intersect(b[0], b[1], s[0], s[1])):
return True
if p[1] == 1:
s = p.segment
a = T.above(s)
b = T.below(s)
# print( a)
# print( b)
# print( type(a))
# print( type(b))
if a != None and b != None and segments_intersect(a[0], a[1], b[0], b[1]):
return True
T.delete(s)
return False
def any_segments_intersect(S):
'''This algorithm takes as input a set S of n line segments, returning the boolean value TRUE if any pair of segments in S intersects, and FALSE otherwise.'''
T = rb_tree()
segment_list = []
point_list = []
for s in S:
segment_list.append(segment(s))
for s in segment_list:
point_list.append(point([s[0][0], 0, s[0][1]], s))
point_list.append(point([s[1][0], 1, s[1][1]], s))
heap_point = max_heap(point_list)
heap_point.heapsort()
for p in heap_point:
if p[1] == 0:
s = p.segment
T.insert(s)
a = T.above(s)
b = T.below(s)
if (a != None and segments_intersect(a[0], a[1], s[0], s[1])) or (b != None and segments_intersect(b[0], b[1], s[0], s[1])):
return True
if p[1] == 1:
s = p.segment
a = T.above(s)
b = T.below(s)
# print a
# print b
# print type(a)
# print type(b)
if a != None and b != None and segments_intersect(a[0], a[1], b[0], b[1]):
return True
T.delete(s)
return False
def y_sort(S):
Y = []
for p in S:
Y.append((p[1], p[0]))
YY = max_heap(Y)
YY.heapsort()
Y = []
for i in range(0, len(YY)):
Y.append((YY[i][1], YY[i][0]))
return Y
def y_sort(S):
Y = []
for p in S:
Y.append((p[1], p[0]))
YY = max_heap(Y)
YY.heapsort()
Y = []
for i in range(0, len(YY)):
Y.append((YY[i][1], YY[i][0]))
return Y
def any_disks_intersect(S):
"""
This algorithm takes as input a set S of n disks represented by its center point and radius, returning the boolean value TRUE if any pair of disks in S intersects, and FALSE otherwise.
:param S:
:return:
"""
T = rb_tree()
point_list = []
disk_list = []
for s in S:
disk_list.append(disk(s))
for s in disk_list:
center_point = s[0]
radius = s[1]
x = center_point[0]
y = center_point[1]
point_list.append(point([x - radius, 0, y], s))
point_list.append(point([x + radius, 1, y], s))
heap_point = max_heap(point_list)
heap_point.heapsort()
print(heap_point)
for p in heap_point:
if p[1] == 0:
s = p.disk
T.insert(s)
a = T.above(s)
b = T.below(s)
print("insert: ", a, b)
if (a is not None
and disks_intersect(a, s)) or (b is not None
and disks_intersect(b, s)):
return True
if p[1] == 1:
s = p.disk
a = T.above(s)
b = T.below(s)
if a is not None and b is not None and disks_intersect(a, b):
return True
T.delete(s)
return False
def three_points_colinear(points_list):
'''An algorithm to determine whether any three points in a set of n points are colinear'''
n = len(points_list)
vectors_list = []
for i in range(n):
for j in range(i + 1, n):
vectors_list.append(vector(points_list[i], points_list[j], i, j))
v0 = vector((1, 0), (0, 0))
heap_vectors = max_heap(vectors_list)
heap_vectors.heapsort()
status = [False] * n
v = heap_vectors[0]
status[v.p1_index] = True
status[v.p2_index] = True
stack = []
stack.append(v.p1_index)
stack.append(v.p2_index)
for i in range(1, len(heap_vectors)):
v = heap_vectors[i]
if v == heap_vectors[i - 1]:
if status[v.p1_index]:
return True
elif status[v.p2_index]:
return True
else:
status[v.p1_index] = True
status[v.p2_index] = True
stack.append(v.p1_index)
stack.append(v.p2_index)
else:
print(len(stack))
print(stack)
for i in range(len(stack)):
status[stack.pop()] = False
stack.append(v.p1_index)
stack.append(v.p2_index)
return False
def x_sort(S):
X = max_heap(S)
X.heapsort()
return X
def x_sort(S):
X = max_heap(S)
X.heapsort()
return X
def test_max_heapify(self):
a = [16, 4, 10, 14, 7, 9, 3, 2, 8, 1]
h = max_heap(a)
h.max_heapify(1)
self.assertEquals(h, [16, 14, 10, 8, 7, 9, 3, 2, 4, 1])
def test_heapsort(self):
a = [4, 1, 3, 3, 16, 9, 10, 14, 8, 7]
h = max_heap(a)
h.heapsort()
self.assertEquals(h, [1, 3, 3, 4, 7, 8, 9, 10, 14, 16])
def test_build_max_heap(self):
a = [4, 1, 3, 2, 16, 9, 10, 14, 8, 7]
h = max_heap(a)
h.build_max_heap()
self.assertEquals(h, [16, 14, 10, 8, 7, 9, 3, 2, 4, 1])
