Problem24

1.package com.yao.Algorithms;  
2.  
3.import java.util.ArrayList;  
4.import java.util.List;  
5./** 
6. *  
7. * @author shuimuqinghua77 @date 2012-4-26下午02:01:16 
8. * 
9. */  
10.public class Problem24 {  
11./** 
12. * 存放数字 
13. */  
14.private static List<Integer> list=new ArrayList<Integer>();  
15.  
16.private static int MILLION=100*100*100;  
17.private static int count=0;  
18.private static StringBuilder millionth=new StringBuilder();  
19.public static void main(String[] args) {  
20.    for(int i=0;i<10;i++)  
21.        list.add(i);  
22.    find(factor(list.size()-1),millionth);  
23.    System.out.println(millionth);  
24.    System.out.println(count);  
25.}  
26./** 
27. * 表示一个全排列的量 
28. * @param size 
29. * @return 
30. */  
31.private static int factor(int size) {  
32.    int factor=1;  
33.    for(int i=1;i<=size;i++){  
34.        factor*=i;  
35.    }  
36.    return factor;  
37.}  
38./** 
39. * 以递归的方式遍历 
40. * @param factor 
41. * @param millionth 
42. * @return 
43. */  
44.private static int find(int factor,StringBuilder millionth) {  
45.    for(int j=0;j<list.size();j++)  
46.    {  
47.        int future=count+factor;  
48.        if(future<MILLION){  
49.            count=future;  
50.        }  
51.        else if(future>MILLION){  
52.            millionth.append(list.get(j));  
53.            list.remove(j);  
54.            return find(factor(list.size()-1),millionth);  
55.        }  
56.        else{  
57.            millionth.append(list.get(j));  
58.            list.remove(j);  
59.            /** 
60.             * 关键部分   剩下的数字应该以倒序添加到digit末尾，也就是从大到小的顺序 
61.             */  
62.            for(int k=list.size()-1;k>=0;k--)  
63.                millionth.append(list.get(k));  
64.            return future;  
65.        }  
66.    }  
67.    return count;  
68.}  
69.}