CSU 1290 DP solves mathematical expectation Problems

Question link: http://acm.csu.edu.cn/OnlineJudge/problem.php? Id = 1290

Question:

Given the number of K, you can generate any number in 0-n-1 each time. The mathematical expectation of the number of K numbers with different integers

1 # include <cstdio> 2 # include <cstring> 3 using namespace STD; 4 # define n 1005 5 double DP [N]; 6 int main () 7 {8 int t, k, n; 9 scanf ("% d", & T); 10 while (t --) {11 scanf ("% d", & K, & N ); 12 DP [1] = 1.00; 13 for (INT I = 2; I <= N; I ++) {14 DP [I] = DP [I-1] + (k-DP [I-1])/K; 15} 16 printf ("%. 5f \ n ", DP [N]); 17} 18 return 0; 19}