Children’s Queue
Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 8602 Accepted Submission(s): 2722
Problem Description
There are many 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?
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?
Input
There 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)
Output
For each test case, there is only one integer means the number of queue satisfied the headmaster’s needs.
Sample Input
1 2 3
Sample Output
1 2 4
Author
SmallBeer (CML)
Source
Recommend
lcy
解题思路：因本题数据过大，用C不好处理，直接用了JAVA。递推公式：a[i] = a[i-1] +a[i-2] + a[i-4].
import java.util.*;
import java.math.BigInteger;;
public class Main {
public static void main(String[] args) {
Scanner as=new Scanner(System.in);
int n;
BigInteger[] a=new BigInteger[1001];
a[0]=BigInteger.ONE;
a[1]=BigInteger.ONE;
a[2]=BigInteger.valueOf(2);
a[3]=BigInteger.valueOf(4);
for(int i=4;i<1001;i++)
a[i]=a[i-1].add(a[i-2]).add(a[i-4]);
while(as.hasNext())
{
n=as.nextInt();
System.out.println(a[n]);
}
}
}