Program for Tower of Hanoi

tower_of_hanoi.java

@@ -0,0 +1,103 @@
+// JAVA recursive function to
+// solve tower of hanoi puzzle
+import java.util.*;
+import java.io.*;
+import java.math.*;
+class GFG
+{
+static void towerOfHanoi(int n, char from_rod,
+                    char to_rod, char aux_rod)
+{
+    if (n == 1)
+    {
+        System.out.println("Move disk 1 from rod "+
+                           from_rod+" to rod "+to_rod);
+        return;
+    }
+    towerOfHanoi(n - 1, from_rod, aux_rod, to_rod);
+    System.out.println("Move disk "+ n + " from rod " +
+                       from_rod +" to rod " + to_rod );
+    towerOfHanoi(n - 1, aux_rod, to_rod, from_rod);
+}
+
+// Driver code
+public static void  main(String args[])
+{
+    int n = 4; // Number of disks
+    towerOfHanoi(n, 'A', 'C', 'B'); // A, B and C are names of rods
+}
+}
+
+
+/*
+-- Output --
+Move disk 1 from rod A to rod B
+Move disk 2 from rod A to rod C
+Move disk 1 from rod B to rod C
+Move disk 3 from rod A to rod B
+Move disk 1 from rod C to rod A
+Move disk 2 from rod C to rod B
+Move disk 1 from rod A to rod B
+Move disk 4 from rod A to rod C
+Move disk 1 from rod B to rod C
+Move disk 2 from rod B to rod A
+Move disk 1 from rod C to rod A
+Move disk 3 from rod B to rod C
+Move disk 1 from rod A to rod B
+Move disk 2 from rod A to rod C
+Move disk 1 from rod B to rod C
+
+*/
+
+/*
+-- Output --
+
+Tower of Hanoi Solution for 4 disks:
+
+A: [4, 3, 2, 1] B: [] C: []
+
+Move disk from rod A to rod B
+A: [4, 3, 2] B: [1] C: []
+
+Move disk from rod A to rod C
+A: [4, 3] B: [1] C: [2]
+
+Move disk from rod B to rod C
+A: [4, 3] B: [] C: [2, 1]
+
+Move disk from rod A to rod B
+A: [4] B: [3] C: [2, 1]
+
+Move disk from rod C to rod A
+A: [4, 1] B: [3] C: [2]
+
+Move disk from rod C to rod B
+A: [4, 1] B: [3, 2] C: []
+
+Move disk from rod A to rod B
+A: [4] B: [3, 2, 1] C: []
+
+Move disk from rod A to rod C
+A: [] B: [3, 2, 1] C: [4]
+
+Move disk from rod B to rod C
+A: [] B: [3, 2] C: [4, 1]
+
+Move disk from rod B to rod A
+A: [2] B: [3] C: [4, 1]
+
+Move disk from rod C to rod A
+A: [2, 1] B: [3] C: [4]
+
+Move disk from rod B to rod C
+A: [2, 1] B: [] C: [4, 3]
+
+Move disk from rod A to rod B
+A: [2] B: [1] C: [4, 3]
+
+Move disk from rod A to rod C
+A: [] B: [1] C: [4, 3, 2]
+
+Move disk from rod B to rod C
+A: [] B: [] C: [4, 3, 2, 1]
+*/