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

123

Sample Output

124

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;}