递推DP URAL 1260 Nudnik Photographer

题目传送门

 /*
     递推DP: dp[i] 表示放i的方案数，最后累加前n-2的数字的方案数
 */
 #include <cstdio>
 #include <algorithm>
 #include <cmath>
 #include <cstring>
 using namespace std;

 const int MAXN = 1e4 + ;
 const int INF = 0x3f3f3f3f;
 int dp[];

 int main(void)        //URAL 1260 Nudnik Photographer
 {
     //freopen ("G.in", "r", stdin);

     int n;
     while (scanf ("%d", &n) == )
     {
         memset (dp, , sizeof (dp));
         dp[] = ;
         for (int i=; i<=n; ++i)
         {
             dp[i] = dp[i-];
             if (i > )
             {
                 dp[i] += dp[i-];
             }
         }

         long long ans = dp[n];
         if (n > )
         {
             for (int i=; i<=n-; ++i)    ans += dp[i];
         }
         printf ("%I64d\n", ans);
     }

     return ;
 }