UVA 10254 十八 The Priest Mathematician

 1 import java.math.*;  
 2 import java.util.Scanner;  
 3   
 4 public class Main {  
 5     public static void main(String args[]){  
 6           
 7         BigInteger f[] = new BigInteger[10010];  
 8         f[0] = BigInteger.valueOf(0);  
 9         f[1] = BigInteger.valueOf(1);  
10         int i = 2;  
11         int k=1;  
12         while(i <= 10000){  
13             BigInteger add = BigInteger.valueOf(1).shiftLeft(k);  
14             for(int j=0; j<k+1 && i<=10000; ++j){  
15                 f[i] = f[i-1].add(add);  
16                 ++i;  
17             }  
18             ++k;  
19         }    
20         Scanner cin = new Scanner(System.in);  
21         while(cin.hasNext()){  
22             int n = cin.nextInt();  
23             System.out.println(f[n]);         
24         }  
25     }  
26 }