Flipping Coins

#include <iostream>
#include <iomanip>

const int N = 400;
const int K = 400;
long double dp[N+1][K+1];

int main() {
	int n, k;
	std::cin >> n >> k;
	for (int i = 0; i <= n; ++i) {
		dp[i][0] = n-i;
	}
	for (int s = 1; s <= k; ++s) {
		dp[0][s] = (dp[0][s-1] + dp[1][s-1]) / 2;
		for (int i = 1; i <= n; ++i) {
			dp[i][s] = (dp[i][s-1] + dp[i-1][s-1]) / 2;
		}
	}
	std::cout << std::fixed << std::setprecision(15) << dp[n][k] << '\n';
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED

Test 14

Verdict: ACCEPTED

Test 15

Verdict: ACCEPTED

Test 16

Verdict: ACCEPTED

Test 17

Verdict: ACCEPTED