Children’s Queue

http://acm.hdu.edu.cn/diy/contest_showproblem.php?pid=1001&cid=22706

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?

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

杭电ACM集训队训练赛（VIII）

#include<iostream> 
using namespace std;
int a[1001][300];
int main()
{    int i,j,n,k;  
  a[1][0] = 1;   
  a[2][0] = 2;   
  a[3][0] = 4;   
  a[4][0] = 7;    
  for(i = 5;i < 1001;i++)    
  {          
      k = 0;          
      for(j = 0;j < 300;j++)          
      {                
          a[i][j] = a[i-1][j] + a[i-2][j] + a[i-4][j] + k;                
          k = a[i][j] / 10;                
          a[i][j] %= 10;          
}    
}    
  while(cin >> n)   
  {             
      i = 299;              
      while(i >= 0 && !a[n][i])                      
          i--;              
      while(i >= 0)                      
          cout << a[n][i--];              
      cout << endl;    }    
  return 0;}