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hdu2606(递推)

 

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=2606

题意:  用1*1,2*2,3*3,4*4的正方形填充4*n的矩形, 问有多少种不同填法。

分析: f[i] = f[i - 1] + f[i - 2] * 4 + f[i - 3] * 2 + f[i - 4] * 1 + 对错位的情况(即2*(f[n-3] + f[n-4] + ...f[0]),  f[0]初始化为1)

#include <cstdio>#include <cstring>#include <cmath>#include <iostream>#include <algorithm>#include <queue>#include <cstdlib>#include <vector>#include <set>#include <map>#define LL long long#define mod 19890907#define inf 0x3f3f3f3f#define N 10010using namespace std;int f[110];void init(){    f[0]=1;f[1]=1;f[2]=5;f[3]=13;    for(int i=4;i<=100;i++)    {        f[i]=(f[i-4]+f[i-3]*2+f[i-2]*4+f[i-1])%mod;        for(int j=3;j<=i;j++)f[i]=(f[i]+2*f[i-j])%mod;    }}int main(){    int n,t;    init();    scanf("%d",&t);    while(t--)    {        scanf("%d",&n);        printf("%d\n",f[n]);    }}
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hdu2606(递推)