题目链接: http://poj.org/problem?id=2506 题目描述: 有2*1和2*2两种瓷片,问铺成2*n的图形有多少种方法? 解题思路: 利用递推思想,2*n可以由2*(n-1)的状态加上一块竖放2*1的瓷片转移得来,也可以由2*(n-2)的状态加上一块2*2的瓷片或者加上两块横放的2*1的瓷片转移得来. 可得出递推公式:dp[n] = dp[n-1] + dp[n-2]*2: ac秘诀: (1):从输出样例可以看出要用大数来表示,大概需要90位左右. (2):2*0不是零种…

Tiling Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 7965   Accepted: 3866 Description In how many ways can you tile a 2xn rectangle by 2x1 or 2x2 tiles? Here is a sample tiling of a 2x17 rectangle. Input Input is a sequence of lines,…

题目大意:原题链接有2×1和2×2两种规格的地板,现要拼2×n的形状,共有多少种情况,首先要做这道题目要先对递推有一定的了解.解题思路:1.假设我们已经铺好了2×(n-1)的情形,则要铺到2×n则只能用2×1的地板2.假设我们已经铺好了2×(n-2)的情形,则要铺到2×n则可以选择1个2×2或两个2×1,故可能有下列三种铺法          其中要注意到第三个会与铺好2×(n-1)的情况重复,故不可取,故可以得到递推式 a[n]=2*a[n-2]+a[n-1]; 然后就是高精度部分,可直接用高…

http://poj.org/problem?id=2506 题意: 思路:递推.a[i]=a[i-1]+2*a[i-2]. 计算的时候是大整数加法.错了好久,忘记考虑1了...晕倒. #include<iostream> #include<string> #include<cstring> #include<cstdio> using namespace std; int n; ][]; void cacl(int i) { int k; ]); ]);…

Tiling Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 7487   Accepted: 3661 Description In how many ways can you tile a 2xn rectangle by 2x1 or 2x2 tiles? Here is a sample tiling of a 2x17 rectangle.  Input Input is a sequence of lines,…

题意: 求sigma phi(n) 思路: 线性递推欧拉函数 (维护前缀和) //By SiriusRen #include <cstdio> using namespace std; #define maxn 1000005 #define int long long int n,p[maxn+100],s[maxn+100],phi[maxn+100],tot; void Phi(){ for(int i=2;i<=maxn;i++){ if(!s[i])p[++tot]=i,phi…

题目:http://poj.org/problem?id=2506 题解:f[n]=f[n-2]*2+f[n-1],主要是大数的相加; 以前做过了的 #include<stdio.h> #include<string.h> ][];//ans数组的第一个下标表示瓷砖数目,第二个表示对应下的方法数 //数组是倒序存储 的 int main() { int n, i, j, count, b, p; while (scanf("%d", &n) != EOF…

题目链接:id=2506">http://poj.org/problem?id=2506 本题用的java解的.由于涉及到大数问题,假设对java中的大数操作不熟悉请点这儿:链接 思路:地推公式f[i]=f[i-1]+2*f[i-2] code: import java.math.*; import java.util.Scanner; public class Main { public static void main(String[] args) { Scanner cin=new…

Description In how many ways can you tile a 2xn rectangle by 2x1 or 2x2 tiles? Here is a sample tiling of a 2x17 rectangle.  Input Input is a sequence of lines, each line containing an integer number 0 <= n <= 250. Output For each line of input, out…

Tiling Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 7437   Accepted: 3635 Description In how many ways can you tile a 2xn rectangle by 2x1 or 2x2 tiles? Here is a sample tiling of a 2x17 rectangle. Input Input is a sequence of lines,…