hdu 1250 Hat's Fibonacci (Java大數計算)
阿新 • • 發佈:2018-11-29
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.
import java.math.BigInteger; import java.util.Scanner; public class Main { public static void main(String[] args) { // TODO Auto-generated method stub Scanner in = new Scanner(System.in); BigInteger[] f = new BigInteger[10005]; f[1] = f[2] = f[3] = f[4] = BigInteger.valueOf(1); //賦值格式 int i; for(i = 5; i <= 10000; i++) { f[i] = f[i-1].add(f[i-2]); f[i] = f[i].add(f[i-3]); f[i] = f[i].add(f[i-4]); } while(in.hasNext()) { int n = in.nextInt(); //當n超過30時,就需要用大數類 System.out.println(f[n]); } } }