Problem7

package com.shui.mu.yao.io.algorithm;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

/**
*
* @author shuimuqinghua77 @date 2011-11-3上午10:56:33
*
*/
/**
* By listing the first six prime numbers: 2, 3, 5, 7, 11, and 13, we can see
* that the 6th prime is 13. What is the 10 001st prime number?
*/
public class Problem7 {
private static List<Long> seed = new ArrayList<Long>();
private static long count=7;
static {
seed.add(2l);
seed.add(3l);
seed.add(5l);

}

public static long findPrime(int index) throws Exception {
while (seed.size()<index) {
if(count==Long.MAX_VALUE)
{
throw new Exception("超过long类型最大值");
}
int flag=0;
for(long l:seed){
if(count%l==0)
{
flag=1;
break;
}

}
if(flag==0)
seed.add(count);
count++;
}
return seed.get(index-1);
}
public static void main(String[] args) throws Exception {
long result=findPrime(10001);
System.out.println(result);
System.out.println(Arrays.toString(seed.toArray()));
}
}
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