hdu 2604 queue #DP#滚动数组

http://acm.hdu.edu.cn/showproblem.php?pid=2604

由f、m组成长度为L的字符串的排列数，满足条件：不含fmf，fff的字串

///DP M<=30,想到打表，结果超了内存，
// 滚动数组过，开始用8个变量也超时了，那样太多复制操作了
#include <stdio.h>

int m,l;
int solve()
{
    if(l == 1)
        return 2 % m;
    int ff[2],fm[2],mm[2],mf[2];
    ff[0] = fm[0] = mm[0] = mf[0] = 1;
    int p,c = 0;
    for(int i = 3; i <= l; ++i)
    {
        c = (i&1);
        p = 1 - c;
        ff[c] = mf[p];
        fm[c] = (mf[p] + ff[p]) % m;
        mf[c] = mm[p];
        mm[c] = (mm[p] + fm[p]) % m;
    }
    return (ff[c] + fm[c] + mf[c] + mm[c] ) % m;
}
int main()
{
    while(scanf("%d%d",&l,&