递归练习

 1 import java.io.IOException;
 2 
 3 public class Digui1 {
 4 
 5     public static void main(String[] args) {
 6         // TODO Auto-generated method stub
 7         Digui1  d= new Digui1();
 8         try {
 9             d.printInput();
10         } catch (IOException e) {
11             e.printStackTrace();
12         }
13     }
14     
15     private void printInput() throws IOException {
16          char i = (char) System.in.read(); 
17          if (i != '#') {
18              printInput();
19          }
20          if (i != '#') {
21              System.out.print(i); 
22          }         
23     }
24 
25 }

 1 import java.io.IOException;
 2 
 3 public class Digui1 {
 4 
 5     int a[] = {1,1,2,3,5,8,13,21,34,55,88};
 6     int low = 0;
 7     int high = 10;
 8     int mid = (low+high)/2;
 9     public static void main(String[] args) {
10         Digui1  d= new Digui1();
11         d.search(34);
12     }
13     
14     private void search(int key)  {
15         
16         if(a[mid] < key) {
17             low = mid+1;
18             mid = (low+high)/2;
19             search(key);
20         }
21         else if(a[mid] > key) {
22             high = mid-1;
23             mid = (low+high)/2;
24             search(key);
25         }
26         else{
27             System.out.print(mid);
28         }
29     }
30 }

 1 public class Digui1 {
 2     static int step;
 3     static int p;
 4     public static void main(String[] args) {
 5         Digui1  d= new Digui1();
 6         d.move(4,'x','y','z');
 7         System.out.println("step:"+step);
 8         System.out.println(p);
 9     }
10     //将n个盘子借助y从x移到z
11     private void move(int n,char x,char y, char z)  {
12         p++;
13         if(n == 1) {
14             System.out.println(x+"→"+z);
15             step++;
16         }else{
17             move(n-1,x,z,y);//将n-1个盘子借助z从x移到y
18             System.out.println(x+"→"+z);
19             step++;
20             move(n-1,y,x,z);//将n-1个盘子借助x从y移到z
21         }        
22     }
23 }

 1 x→y
 2 x→z
 3 y→z
 4 x→y
 5 z→x
 6 z→y
 7 x→y
 8 x→z
 9 y→z
10 y→x
11 z→x
12 y→z
13 x→y
14 x→z
15 y→z
16 step:15
17 15