1栈和队列--用栈来求解汉诺塔问题

public static void main(String[] args) {
int num = 4;

// solution 1
int steps1 = hanoiProblem1(num, "left", "mid", "right");
System.out.println("It will move " + steps1 + " steps.");
}

public static int hanoiProblem1(int num, String left, String mid,
String right) {
if (num < 1) {
return 0;
}
return process(num, left, mid, right, left, right);
}

public static int process(int num, String left, String mid, String right,String from, String to) {
if (num == 1) {
if (from.equals(mid) || to.equals(mid)) {
System.out.println("Move 1 from " + from + " to " + to);
return 1;
} else {
System.out.println("Move 1 from " + from + " to " + mid);
System.out.println("Move 1 from " + mid + " to " + to);
return 2;
}
}
if (from.equals(mid) || to.equals(mid)) {
String another = (from.equals(left) || to.equals(left)) ? right : left;
int part1 = process(num - 1, left, mid, right, from, another);
int part2 = 1;
System.out.println("Move " + num + " from " + from + " to " + to);
int part3 = process(num - 1, left, mid, right, another, to);
return part1 + part2 + part3;
} else {
int part1 = process(num - 1, left, mid, right, from, to);
int part2 = 1;
System.out.println("Move " + num + " from " + from + " to " + mid);
int part3 = process(num - 1, left, mid, right, to, from);
int part4 = 1;
System.out.println("Move " + num + " from " + mid + " to " + to);
int part5 = process(num - 1, left, mid, right, from, to);
return part1 + part2 + part3 + part4 + part5;
}
}