CODEVS——T 2956 排队问题

 1 #include <cstdio>
 2 
 3 int n,ans;
 4 
 5 void DFS(int sum)
 6 {
 7     if(sum>n) return ;
 8     if(sum==n) { ans++; return ; }
 9     if(sum+2<=n) DFS(sum+2);
10     if(sum+3<=n) DFS(sum+3);
11 }
12 
13 int Presist()
14 {
15     scanf("%d",&n);
16     DFS(0);
17     printf("%d\n",ans);
18     return 0;
19 }
20 
21 int Aptal=Presist();
22 int main(int argc,char*argv[]){;}

 1 #include <cstdio>
 2 
 3 int n,ans;
 4 long long f[155];
 5 
 6 int Presist()
 7 {
 8     scanf("%d",&n);
 9     f[2]=f[3]=1;
10     for(int i=4; i<=n; ++i) f[i]=f[i-2]+f[i-3];
11     printf("%lld\n",f[n]);
12     return 0;
13 }
14 
15 int Aptal=Presist();
16 int main(int argc,char*argv[]){;}