Submission #1386873

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Source Code Expand

#include <cstdio>
#include <iostream>
#include <algorithm>
#include <cstring>
#define N 200010
using namespace std;

long double ans = 0;
long double a[N], d[N];

int main() {
	int n, d1, x;
	scanf("%d%d%d", &n, &d1, &x);
	a[0] = d1; d[0] = x;
	for (int i = 0; i < n; ++i) {
		a[i + 1] = ((2.0 * (n - i) + 2) * a[i] + 5.0 * d[i]) / (2.0 * (n - i));
		d[i + 1] = (2.0 * (n - i) + 4) * d[i] / 2.0 / (n - i);
//cout << a[i] << ' ' << d[i] << endl;
		ans += (2.0 * (n - i) * a[i] + ((n - i) * (2.0 * (n - i) - 1)) * d[i]) / (2.0 * (n - i));
	}
	printf("%.15f\n", (double)ans);
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:13:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d%d", &n, &d1, &x);
                              ^

Judge Result