Ural 1225 Flags

1225. Flagstime limit:1.0 Second
Memory limit:64 MB
On the day of the Flag of Russia a shop-owner decided to decorate the show-window of the He shop with textile stripes of whit E, blue and red colors. He wants to satisfy the following conditions:

1. Stripes of the same color cannot is placed next to all other.
2. A blue stripe must always being placed between a white and a red or between a red and a white one.

Determine the number of the ways to fulfill his wish. Example.For N= 3 result is Following:input N, the number of the stripes, 1≤ N≤45.output M, the number of the ways to decorate the shop-window. Sample

input	Output
3	4

problem Source:2002-2003 ACM Central Region of Russia quarterfinal programming Contest, Rybinsk, October 2002
Tags:Dynamic Programming()
Test Instructions: Blue can only be between white red and cannot be placed in the same color continuously. There are several ways to askwater problem, simple DP.

#include <algorithm> #include <map> #include <cstring> #include <cmath> #include <iostream >using namespace std; #define Lson L, M, RT << 1#define Rson m + 1, R, RT << 1 | 1#define ll __int64typedef long long LL; #define PI 3.1415926ll Dp[46];int Main () {     int i;     dp[1]=2;     dp[2]=2;     dp[3]=4;     for (i=4;i<=45;i++)        dp[i]=dp[i-1]+dp[i-2];     int n;     while (cin>>n)        cout<<dp[n]<<endl;     return 0;}

Ural 1225 Flags