Question
can you please implement this code in Data structure : linked list in PYTHON make sure in WORKS thnks ------------------------------------------------------------------------------------------------------------- import time from functools import
can you please implement this code in Data structure : linked list in PYTHON make sure in WORKS
thnks
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import time from functools import cmp_to_key
# A class used to store the x and y coordinates of points class Point:
def __init__(self, x = None, y = None):
self.x = x
self.y = y
# A global point needed for sorting points with reference # to the first point p0 = Point(0, 0)
# A utility function to find next to top in a stack def nextToTop(S):
return S[-2]
# A utility function to return square of distance # between p1 and p2 def distSq(p1, p2):
return ((p1.x - p2.x) * (p1.x - p2.x) +
(p1.y - p2.y) * (p1.y - p2.y))
# To find orientation of ordered triplet (p, q, r). # The function returns following values # 0 --> p, q and r are collinear # 1 --> Clockwise # 2 --> Counterclockwise def orientation(p, q, r):
val = ((q.y - p.y) * (r.x - q.x) -
(q.x - p.x) * (r.y - q.y))
if val == 0:
return 0 # collinear
elif val > 0:
return 1 # clock wise
else:
return 2 # counterclock wise
# A function used by cmp_to_key function to sort an array of # points with respect to the first point def compare(p1, p2):
# Find orientation o = orientation(p0, p1, p2) if o == 0: if distSq(p0, p2) >= distSq(p0, p1): return -1 else: return 1 else: if o == 2: return -1 else: return 1
# Prints convex hull of a set of n points. def convexHull(points, n):
# Find the bottommost point takes O(n) ymin = points[0].y
min = 0
for i in range(1, n): y = points[i].y
# Pick the bottom-most or choose the left # most point in case of tie if ((y < ymin) or (ymin == y and points[i].x < points[min].x)): ymin = points[i].y min = i
# Place the bottom-most point at first position points[0], points[min] = points[min], points[0]
# Sort n-1 points with respect to the first point. O(nlogn) # A point p1 comes before p2 in sorted output if p2 # has larger polar angle (in counterclockwise # direction) than p1 p0 = points[0]
points = sorted(points, key=cmp_to_key(compare))
# If two or more points make same angle with p0, # Remove all but the one that is farthest from p0 # Remember that, in above sorting, our criteria was # to keep the farthest point at the end when more than # one points have same angle. m = 1 # Initialize size of modified array
for i in range(1, n): # Keep removing i while angle of i and i+1 is same # with respect to p0 while ((i < n - 1) and (orientation(p0, points[i], points[i + 1]) == 0)): i += 1 points[m] = points[i] m += 1 # Update size of modified array # If modified array of points has less than 3 points, # convex hull is not possible if m < 3: return # Create an empty stack and push first three points O(n) # to it. S = [] S.append(points[0]) S.append(points[1]) S.append(points[2]) # Process remaining n-3 points for i in range(3, m): # Keep removing top while the angle formed by # points next-to-top, top, and points[i] makes # a non-left turn while ((len(S) > 1) and (orientation(nextToTop(S), S[-1], points[i]) != 2)): S.pop() S.append(points[i]) # Now stack has the output points, O(n) # print contents of stack while S: p = S[-1] print("(" + str(p.x) + ", " + str(p.y) + ")") S.pop()
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