"""turtledemo/sorting_animation.py
A minimal sorting algorithm animation:
Sorts a shelf of 10 blocks using insertion
sort, selection sort and quicksort.
Shelves are implemented using builtin lists.
Blocks are turtles with shape "square", but
stretched to rectangles by shapesize()
"""
from turtle import *
import random
class Block(Turtle):
def __init__(self, size):
self.size = size
Turtle.__init__(self, shape="square", visible=False)
self.pu()
self.shapesize(size * 1.5, 1.5, 2) # square-->rectangle
self.fillcolor("black")
self.st()
def glow(self):
self.fillcolor("red")
def unglow(self):
self.fillcolor("black")
def __repr__(self):
return "Block size: {0}".format(self.size)
class Shelf(list):
def __init__(self, y):
"create a shelf. y is y-position of first block"
self.y = y
self.x = -150
def push(self, d):
width, _, _ = d.shapesize()
# align blocks by the bottom edge
y_offset = width / 2 * 20
d.sety(self.y + y_offset)
d.setx(self.x + 34 * len(self))
self.append(d)
def _close_gap_from_i(self, i):
for b in self[i:]:
xpos, _ = b.pos()
b.setx(xpos - 34)
def _open_gap_from_i(self, i):
for b in self[i:]:
xpos, _ = b.pos()
b.setx(xpos + 34)
def pop(self, key):
b = list.pop(self, key)
b.glow()
b.sety(200)
self._close_gap_from_i(key)
return b
def insert(self, key, b):
self._open_gap_from_i(key)
list.insert(self, key, b)
b.setx(self.x + 34 * key)
width, _, _ = b.shapesize()
# align blocks by the bottom edge
y_offset = width / 2 * 20
b.sety(self.y + y_offset)
b.unglow()
def isort(shelf):
length = len(shelf)
for i in range(1, length):
hole = i
while hole > 0 and shelf[i].size < shelf[hole - 1].size:
hole = hole - 1
shelf.insert(hole, shelf.pop(i))
return
def ssort(shelf):
length = len(shelf)
for j in range(0, length - 1):
imin = j
for i in range(j + 1, length):
if shelf[i].size < shelf[imin].size:
imin = i
if imin != j:
shelf.insert(j, shelf.pop(imin))
def partition(shelf, left, right, pivot_index):
pivot = shelf[pivot_index]
shelf.insert(right, shelf.pop(pivot_index))
store_index = left
for i in range(left, right): # range is non-inclusive of ending value
if shelf[i].size < pivot.size:
shelf.insert(store_index, shelf.pop(i))
store_index = store_index + 1
shelf.insert(store_index, shelf.pop(right)) # move pivot to correct position
return store_index
def qsort(shelf, left, right):
if left < right:
pivot_index = left
pivot_new_index = partition(shelf, left, right, pivot_index)
qsort(shelf, left, pivot_new_index - 1)
qsort(shelf, pivot_new_index + 1, right)
def randomize():
disable_keys()
clear()
target = list(range(10))
random.shuffle(target)
for i, t in enumerate(target):
for j in range(i, len(s)):
if s[j].size == t + 1:
s.insert(i, s.pop(j))
show_text(instructions1)
show_text(instructions2, line=1)
enable_keys()
def show_text(text, line=0):
line = 20 * line
goto(0,-250 - line)
write(text, align="center", font=("Courier", 16, "bold"))
def start_ssort():
disable_keys()
clear()
show_text("Selection Sort")
ssort(s)
clear()
show_text(instructions1)
show_text(instructions2, line=1)
enable_keys()
def start_isort():
disable_keys()
clear()
show_text("Insertion Sort")
isort(s)
clear()
show_text(instructions1)
show_text(instructions2, line=1)
enable_keys()
def start_qsort():
disable_keys()
clear()
show_text("Quicksort")
qsort(s, 0, len(s) - 1)
clear()
show_text(instructions1)
show_text(instructions2, line=1)
enable_keys()
def init_shelf():
global s
s = Shelf(-200)
vals = (4, 2, 8, 9, 1, 5, 10, 3, 7, 6)
for i in vals:
s.push(Block(i))
def disable_keys():
onkey(None, "s")
onkey(None, "i")
onkey(None, "q")
onkey(None, "r")
def enable_keys():
onkey(start_isort, "i")
onkey(start_ssort, "s")
onkey(start_qsort, "q")
onkey(randomize, "r")
onkey(bye, "space")
def main():
getscreen().clearscreen()
ht(); penup()
init_shelf()
show_text(instructions1)
show_text(instructions2, line=1)
enable_keys()
listen()
return "EVENTLOOP"
instructions1 = "press i for insertion sort, s for selection sort, q for quicksort"
instructions2 = "spacebar to quit, r to randomize"
if __name__=="__main__":
msg = main()
mainloop()
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