HDOJ 1297 Children's Queue

JAVA large number ....

Children's Queue Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others)
Total Submission (s): 10390 Accepted Submission (s): 3333


Problem DescriptionThere are already students in PHT School. one day, the headmaster whose name is PigHeader wanted all students stand in a line. he prescribed that girl can not be in single. in other words, either no girl in the queue or more than one girl stands side by side. the case n = 4 (n is the number of children) is like
FFFF, FFFM, MFFF, FFMM, MFFM, MMFF, MMMM
Here F stands for a girl and M stands for a boy. the total number of queue satisfied the headmaster's needs is 7. can you make a program to find the total number of queue with n children?

InputThere are multiple cases in this problem and ended by the EOF. In each case, there is only one integer n means the number of children (1 <=n <= 1000)
OutputFor each test case, there is only one integer means the number of queue satisfied the headmaster's needs.
Sample Input

123

Sample Output

124

AuthorSmallBeer (CRF)
Source hangdian ACM training team training competition (VIII)

import java.util.*;import java.math.*;public class Main{public static void main(String[] args){Scanner cin=new Scanner(System.in);BigInteger[] a=new BigInteger[1100];a[1]=BigInteger.valueOf(1);a[2]=BigInteger.valueOf(2);a[3]=BigInteger.valueOf(4);a[4]=BigInteger.valueOf(7);for(int i=5;i<=1000;i++){a[i]=a[i-4].add(a[i-2].add(a[i-1]));}while(cin.hasNextInt()){int n=cin.nextInt();System.out.println(a[n]);}}}