DFS Codeforces Round #299 (Div. 2) B. Tavas and SaDDas

题目传送门

 /*
     DFS：按照长度来DFS，最后排序
 */
 #include <cstdio>
 #include <algorithm>
 #include <cstring>
 #include <iostream>
 #include <cmath>
 #include <vector>
 using namespace std;

 const int MAXN = 1e3 + ;
 const int INF = 0x3f3f3f3f;
 int b[] = {, };
 int a[MAXN];
 int tot;

 void DFS(int now, int l, int len)
 {
     if (l == len)    {a[++tot] = now;    return ;}
     for (int i=; i<; ++i)
     {
         int tmp = now *  + b[i];
         DFS (tmp, l + , len);
     }
 }

 void solve(void)
 {
     tot = ;
     for (int i=; i<=; ++i)
     {
         DFS (, , i);
     }
     sort (a+, a++tot);
     //for (int i=1; i<=tot; ++i)    printf ("%d ", a[i]);
 }

 int main(void)        //Codeforces Round #299 (Div. 2) B. Tavas and SaDDas
 {
     solve ();
     int n;
     while (scanf ("%d", &n) == )
     {
         printf ("%d\n", lower_bound (a+, a++tot, n) - a);
     }

     return ;
 }