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#!/usr/bin/env python3
"""
sorting_animation.py
A minimal sorting algorithm animation:
Sorts a shelf of 10 blocks using insertion
sort, selection sort and quicksort.
Shelfs are implemented using builtin lists.
Blocks are turtles with shape "square", but
stretched to rectangles by shapesize()
---------------------------------------
To exit press space button
---------------------------------------
"""
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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