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* Retranslate the complete English edition from Simplified Chinese * Polish three English explanations after reader-focused review
54 lines
1.4 KiB
Python
54 lines
1.4 KiB
Python
"""
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File: hanota.py
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Created Time: 2023-07-16
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Author: krahets (krahets@163.com)
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"""
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def move(src: list[int], tar: list[int]):
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"""Move one disk"""
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# Take a disk from the top of src
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pan = src.pop()
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# Place the disk on top of tar
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tar.append(pan)
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def dfs(i: int, src: list[int], buf: list[int], tar: list[int]):
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"""Solve the Tower of Hanoi problem f(i)"""
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# If this subproblem has only one disk to move, move it directly from src to tar
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if i == 1:
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move(src, tar)
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return
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# Subproblem f(i-1): move the top i-1 disks from src to buf using tar
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dfs(i - 1, src, tar, buf)
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# Subproblem f(1): move the remaining disk of this subproblem from src to tar
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move(src, tar)
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# Subproblem f(i-1): move the top i-1 disks from buf to tar using src
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dfs(i - 1, buf, src, tar)
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def solve_hanota(A: list[int], B: list[int], C: list[int]):
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"""Solve the Tower of Hanoi problem"""
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n = len(A)
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# Move the top n disks from A to C using B
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dfs(n, A, B, C)
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"""Driver code"""
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if __name__ == "__main__":
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# The end of each list represents the top of the peg
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A = [5, 4, 3, 2, 1]
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B = []
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C = []
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print("Initial state:")
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print(f"A = {A}")
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print(f"B = {B}")
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print(f"C = {C}")
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solve_hanota(A, B, C)
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print("After moving the disks:")
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print(f"A = {A}")
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print(f"B = {B}")
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print(f"C = {C}")
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