155 lines
4.5 KiB
Python
Executable File
155 lines
4.5 KiB
Python
Executable File
#!/usr/bin/env python3
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"""
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Animated Towers of Hanoi using Tk with optional bitmap file in background.
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Usage: hanoi.py [n [bitmapfile]]
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n is the number of pieces to animate; default is 4, maximum 15.
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The bitmap file can be any X11 bitmap file (look in /usr/include/X11/bitmaps for
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samples); it is displayed as the background of the animation. Default is no
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bitmap.
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"""
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from tkinter import Tk, Canvas
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# Basic Towers-of-Hanoi algorithm: move n pieces from a to b, using c
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# as temporary. For each move, call report()
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def hanoi(n, a, b, c, report):
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if n <= 0: return
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hanoi(n-1, a, c, b, report)
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report(n, a, b)
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hanoi(n-1, c, b, a, report)
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# The graphical interface
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class Tkhanoi:
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# Create our objects
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def __init__(self, n, bitmap=None):
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self.n = n
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self.tk = tk = Tk()
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self.canvas = c = Canvas(tk)
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c.pack()
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width, height = tk.getint(c['width']), tk.getint(c['height'])
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# Add background bitmap
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if bitmap:
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self.bitmap = c.create_bitmap(width//2, height//2,
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bitmap=bitmap,
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foreground='blue')
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# Generate pegs
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pegwidth = 10
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pegheight = height//2
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pegdist = width//3
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x1, y1 = (pegdist-pegwidth)//2, height*1//3
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x2, y2 = x1+pegwidth, y1+pegheight
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self.pegs = []
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p = c.create_rectangle(x1, y1, x2, y2, fill='black')
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self.pegs.append(p)
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x1, x2 = x1+pegdist, x2+pegdist
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p = c.create_rectangle(x1, y1, x2, y2, fill='black')
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self.pegs.append(p)
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x1, x2 = x1+pegdist, x2+pegdist
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p = c.create_rectangle(x1, y1, x2, y2, fill='black')
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self.pegs.append(p)
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self.tk.update()
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# Generate pieces
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pieceheight = pegheight//16
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maxpiecewidth = pegdist*2//3
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minpiecewidth = 2*pegwidth
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self.pegstate = [[], [], []]
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self.pieces = {}
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x1, y1 = (pegdist-maxpiecewidth)//2, y2-pieceheight-2
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x2, y2 = x1+maxpiecewidth, y1+pieceheight
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dx = (maxpiecewidth-minpiecewidth) // (2*max(1, n-1))
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for i in range(n, 0, -1):
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p = c.create_rectangle(x1, y1, x2, y2, fill='red')
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self.pieces[i] = p
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self.pegstate[0].append(i)
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x1, x2 = x1 + dx, x2-dx
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y1, y2 = y1 - pieceheight-2, y2-pieceheight-2
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self.tk.update()
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self.tk.after(25)
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# Run -- never returns
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def run(self):
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while True:
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hanoi(self.n, 0, 1, 2, self.report)
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hanoi(self.n, 1, 2, 0, self.report)
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hanoi(self.n, 2, 0, 1, self.report)
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hanoi(self.n, 0, 2, 1, self.report)
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hanoi(self.n, 2, 1, 0, self.report)
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hanoi(self.n, 1, 0, 2, self.report)
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# Reporting callback for the actual hanoi function
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def report(self, i, a, b):
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if self.pegstate[a][-1] != i: raise RuntimeError # Assertion
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del self.pegstate[a][-1]
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p = self.pieces[i]
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c = self.canvas
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# Lift the piece above peg a
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ax1, ay1, ax2, ay2 = c.bbox(self.pegs[a])
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while True:
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x1, y1, x2, y2 = c.bbox(p)
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if y2 < ay1: break
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c.move(p, 0, -1)
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self.tk.update()
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# Move it towards peg b
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bx1, by1, bx2, by2 = c.bbox(self.pegs[b])
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newcenter = (bx1+bx2)//2
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while True:
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x1, y1, x2, y2 = c.bbox(p)
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center = (x1+x2)//2
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if center == newcenter: break
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if center > newcenter: c.move(p, -1, 0)
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else: c.move(p, 1, 0)
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self.tk.update()
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# Move it down on top of the previous piece
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pieceheight = y2-y1
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newbottom = by2 - pieceheight*len(self.pegstate[b]) - 2
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while True:
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x1, y1, x2, y2 = c.bbox(p)
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if y2 >= newbottom: break
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c.move(p, 0, 1)
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self.tk.update()
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# Update peg state
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self.pegstate[b].append(i)
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def main():
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import sys
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# First argument is number of pegs, default 4
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if sys.argv[1:]:
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n = int(sys.argv[1])
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else:
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n = 4
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# Second argument is bitmap file, default none
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if sys.argv[2:]:
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bitmap = sys.argv[2]
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# Reverse meaning of leading '@' compared to Tk
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if bitmap[0] == '@': bitmap = bitmap[1:]
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else: bitmap = '@' + bitmap
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else:
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bitmap = None
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# Create the graphical objects...
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h = Tkhanoi(n, bitmap)
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# ...and run!
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h.run()
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# Call main when run as script
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if __name__ == '__main__':
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main()
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