UVA 10918 Tri Tiling

题意：求几种方法构建成3*n的矩形，小的矩形只有1*2的，仿照uva 10359的思路f(n)=3*f(n-2)+2*f(n-4)，递推出公式：f(n)=4*f(n-2)-f(n-4)，当n是奇数的时候,f(n)=0

#include <iostream>#include <cstdio>#include <cstring>using namespace std;const int MAXN = 100;int f[MAXN];int main(){    f[0] = 1;    f[1] = 0;    f[2] = 3;    for (int i = 3; i < MAXN; i++){        if (i & 1)            f[i] = 0;        else f[i] = 4 * f[i-2] - f[i-4];    }    int n;    while (scanf("%d",&n) != EOF && n != -1)        printf("%d\n",f[n]);    return 0;}