该题的源地址： https://codeforces.com/gym/103118/problem/G

我的答案：

#include<bits/stdc++.h>
using namespace std;
const int N = 100010;
int n, k;
double q[N];
vector<int>A;
int main()
{
	cin >> n >> k;
	double sum = 0;
	for (int i = 0; i < n; i++)
	{
		cin >> q[i];
		sum += q[i];
	}
	double m = sum / n;
	if (m == 0)
	{
		cout << 0 << ".";
		for (int i = 0; i < k; i++)
		{
			cout << 0;
		}
	}
	else
	{
		long long  l = m * pow(10, k);

		while (l != 0)
		{
			A.push_back(l % 10);
			l = l / 10;
		}
		for (int i = A.size() - 1; i >= 0; i--)

		{
			if (i == k - 1)
				cout << ".";
			cout << A[i];

		}
	}

	return 0;
}

求大佬帮我看看 ，我这个题解对于该题哪里有问题讷；