60 lines
1.9 KiB
C#
60 lines
1.9 KiB
C#
/**
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* File: hanota.cs
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* Created Time: 2023-07-18
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* Author: hpstory (hpstory1024@163.com)
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*/
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namespace hello_algo.chapter_divide_and_conquer;
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public class hanota {
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/* Move a disc */
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void Move(List<int> src, List<int> tar) {
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// Take out a disc from the top of src
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int pan = src[^1];
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src.RemoveAt(src.Count - 1);
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// Place the disc on top of tar
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tar.Add(pan);
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}
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/* Solve the Tower of Hanoi problem f(i) */
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void DFS(int i, List<int> src, List<int> buf, List<int> tar) {
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// If only one disc remains on src, move it 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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}
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// Subproblem f(i-1): move the top i-1 discs from src with the help of tar to buf
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DFS(i - 1, src, tar, buf);
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// Subproblem f(1): move the remaining one disc from src to tar
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Move(src, tar);
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// Subproblem f(i-1): move the top i-1 discs from buf with the help of src to tar
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DFS(i - 1, buf, src, tar);
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}
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/* Solve the Tower of Hanoi problem */
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void SolveHanota(List<int> A, List<int> B, List<int> C) {
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int n = A.Count;
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// Move the top n discs from A with the help of B to C
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DFS(n, A, B, C);
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}
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[Test]
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public void Test() {
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// The tail of the list is the top of the pillar
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List<int> A = [5, 4, 3, 2, 1];
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List<int> B = [];
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List<int> C = [];
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Console.WriteLine("Initial state:");
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Console.WriteLine("A = " + string.Join(", ", A));
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Console.WriteLine("B = " + string.Join(", ", B));
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Console.WriteLine("C = " + string.Join(", ", C));
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SolveHanota(A, B, C);
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Console.WriteLine("After the discs are moved:");
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Console.WriteLine("A = " + string.Join(", ", A));
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Console.WriteLine("B = " + string.Join(", ", B));
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Console.WriteLine("C = " + string.Join(", ", C));
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}
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}
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