Java 示例 - 解决河内塔

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  问题描述

  如何使用方法解决河内塔问题？
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  解决方案

  这个例子展示了使用方法解决河内塔问题的方法（3 个磁盘）。

  
  public class MainClass {
     public static void main(String[] args) {
        int nDisks = 3;
        doTowers(nDisks, 'A', 'B', 'C');
     }
     public static void doTowers(int topN, char from, char inter, char to) {
        if (topN == 1) {
           System.out.println("Disk 1 from " + from + " to " + to);
        } else {
           doTowers(topN - 1, from, to, inter);
           System.out.println("Disk " + topN + " from " + from + " to " + to);
           doTowers(topN - 1, inter, from, to);
        }
     }
  }
  

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  结果

  上面的代码示例将产生以下结果。

  
  Disk 1 from A to C
  Disk 2 from A to B
  Disk 1 from C to B
  Disk 3 from A to C
  Disk 1 from B to A
  Disk 2 from B to C
  Disk 1 from A to C
  

  以下是河内塔的另一个示例

  
  public class TowersOfHanoi {
     public static void move(int n, int startPole, int endPole) {
        if (n == 0) {
           return;
        } 
        int intermediatePole = 6 - startPole - endPole;
        move(n-1, startPole, intermediatePole);
        System.out.println("Move " +n + " from " + startPole + " to " +endPole);
        move(n-1, intermediatePole, endPole);
     } 
     public static void main(String[] args) {
        move(5, 1, 3);
     }
  }
  

  上面的代码示例将产生以下结果。

  
  Move 1 from 1 to 3
  Move 2 from 1 to 2
  Move 1 from 3 to 2
  Move 3 from 1 to 3
  Move 1 from 2 to 1
  Move 2 from 2 to 3
  Move 1 from 1 to 3
  Move 4 from 1 to 2
  Move 1 from 3 to 2
  Move 2 from 3 to 1
  Move 1 from 2 to 1
  Move 3 from 3 to 2
  Move 1 from 1 to 3
  Move 2 from 1 to 2
  Move 1 from 3 to 2
  Move 5 from 1 to 3
  Move 1 from 2 to 1
  Move 2 from 2 to 3
  Move 1 from 1 to 3
  Move 3 from 2 to 1
  Move 1 from 3 to 2
  Move 2 from 3 to 1
  Move 1 from 2 to 1
  Move 4 from 2 to 3
  Move 1 from 1 to 3
  Move 2 from 1 to 2
  Move 1 from 3 to 2
  Move 3 from 1 to 3
  Move 1 from 2 to 1
  Move 2 from 2 to 3
  Move 1 from 1 to 3