1.package com.shui.mu.yao.io.algorithm;
2.
3.import java.util.ArrayList;
4.import java.util.Arrays;
5.import java.util.List;
6.
7./**
8. *
9. * @author shuimuqinghua77 @date 2011-11-3上午10:56:33
10. *
11. */
12./**
13. * By listing the first six prime numbers: 2, 3, 5, 7, 11, and 13, we can see
14. * that the 6th prime is 13. What is the 10 001st prime number?
15. */
16.public class Problem7 {
17. private static List<Long> seed = new ArrayList<Long>();
18. private static long count=7;
19. static {
20. seed.add(2l);
21. seed.add(3l);
22. seed.add(5l);
23.
24. }
25.
26. public static long findPrime(int index) throws Exception {
27. while (seed.size()<index) {
28. if(count==Long.MAX_VALUE)
29. {
30. throw new Exception("超过long类型最大值");
31. }
32. int flag=0;
33. for(long l:seed){
34. if(count%l==0)
35. {
36. flag=1;
37. break;
38. }
39.
40. }
41. if(flag==0)
42. seed.add(count);
43. count++;
44. }
45. return seed.get(index-1);
46. }
47. public static void main(String[] args) throws Exception {
48. long result=findPrime(10001);
49. System.out.println(result);
50. System.out.println(Arrays.toString(seed.toArray()));
51. }
52.}
