SPOJ Favorite Dice（期望DP入門）

https://vjudge.net/problem/SPOJ-FAVDICE

https://blog.csdn.net/myjs999/article/details/81022546

 1 #define IO std::ios::sync_with_stdio(0),cin.tie(0),cout.tie(0);
 2 #define bug(x) cout<<#x<<" is "<<x<<endl
 3 #include <bits/stdc++.h>
 4 #define iter ::iterator
 5 using namespace  std;
 6 typedef long long ll;
 7 typedef pair<int,ll>P;
 8 #define pb push_back
 9 #define mk make_pair
10 #define se second
11 #define fi first
12 #define rs o*2+1
13 #define ls o*2
14 const ll inf=1e18;
15 
16 const int N=1e5+5;
17 
18 int T;
19 
20 int n,m;
21  
22 double d[N];
23 
24 int main(){
25 
26     IO;
27     cin>>T;
28     cout.precision(2);
29     cout.setf(ios::fixed);
30     while(T--){
31         cin>>n;
32         d[n]=0;
33         for(int i=n-1;i>=0;i--){
34             d[i]=(double)n/(n-i)+d[i+1];
35         }
36         
37         cout<<d[0]<<endl;
38     }
39 
40 
41 
42 }