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
[i])

i--;

while(i >= 0)

cout << a
[i--];

cout << endl; }

return 0;}