Codeforces Round #259 (Div. 2) C - Little Pony and Expected Maximum

 1 #include <iostream>
 2 #include <cstring>
 3 #include <cstdlib>
 4 #include <cmath>
 5 #include <cstdio>
 6 #include <vector>
 7 #include <algorithm>
 8 #define LL long long
 9 using namespace std;
10 
11 int main()
12 {
13     int i;
14     double ans, n, m, temp, pre;
15     while(cin>>m>>n)
16     {
17         ans = pow(1.0/m, n);
18         pre = ans;
19         for(i = 2; i <= m; i++)
20         {
21             temp = pow(i/m, n);
22             ans += (temp-pre)*i;
23             pre = temp;
24         }
25 
26         printf("%.4lf\n", ans);
27     }
28     return 0;
29 }