| #!/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() |