hdu1250 Hat's Fibonacci(高精度加)

Hat's Fibonacci Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 5097    Accepted Submission(s): 1713

Problem Description

A Fibonacci sequence is calculated by adding the previous two members the sequence, with the first two members being both 1.F(1) = 1, F(2) = 1, F(3) = 1,F(4) = 1, F(n>4) = F(n - 1) + F(n-2) + F(n-3) + F(n-4)Your task is to take a number as input, and print that Fibonacci number.

 

Input

Each line will contain an integers. Process to end of file.

 

Output

For each case, output the result in a line.

 

Sample Input

   
   
   
   

    
    
    
    100
   
   
   
   

 

Sample Output

    
    
    
    

     
     
     
     4203968145672990846840663646


Note:
No generated Fibonacci number in excess of 2005 digits will be in the test data, ie. F(20) = 66526 has 5 digits.
    
    
    
    

 

Author

戴帽子的

 

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import java.math.BigInteger;   
import java.util.Scanner;   

public class Main {   
  
    public static void main(String[] args) {   
        Scanner cin = new Scanner((System.in));   
        int  n;
        BigInteger[] f = new BigInteger[10000];
        f[1] = BigInteger.ONE;
        f[2] = BigInteger.ONE;
        f[3] = BigInteger.ONE;
        f[4] = BigInteger.ONE;
        for(int i=5; i<f.length;i++) 
        	f[i] = f[i-1].add(f[i-2].add(f[i-3].add(f[i-4])));
        while(cin.hasNext()){
        	n = cin.nextInt();
        	System.out.println(f[n]);
        }
    }   
}