55 lines
1.3 KiB
Dart
55 lines
1.3 KiB
Dart
/**
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* File: hanota.dart
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* Created Time: 2023-08-10
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* Author: liuyuxin (gvenusleo@gmail.com)
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*/
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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.removeLast();
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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.length;
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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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/* Driver Code */
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void main() {
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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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print("Initial state:");
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print("A = $A");
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print("B = $B");
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print("C = $C");
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solveHanota(A, B, C);
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print("After the discs are moved:");
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print("A = $A");
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print("B = $B");
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print("C = $C");
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}
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