这辈子跟精度过不去了……

#include<bits/stdc++.h>
using namespace std;

const int N = 1e5 + 10;
int n, s, t, a[N];
double sum[N];

bool check(double x){
	for(int i=1;i<=n;i++)
		sum[i] = sum[i - 1] + double(a[i]) - x;
	deque<int> q;
	for(int i=s;i<=n;i++){
		while(!q.empty() && sum[q.back()] - sum[i - s] > 1e-6)
			q.pop_back();
		q.push_back(i - s);
		
		if(!q.empty() && i - q.front() > t)
			q.pop_front();
		if(!q.empty() && sum[i] - sum[q.front()] >= 1e-6)
			return 1;
	}
	return 0;
}

int main(){
	scanf("%d%d%d", &n, &s, &t);
	for(int i=1;i<=n;i++)
		scanf("%d", &a[i]);
	double l = -10000, r = 10000;
	while(r - l > 1e-6){
		double mid = (l + r) / 2.0;
		if(check(mid))
			l = mid + 1.0;
		else
			r = mid - 1.0;
	}
	printf("%0.3lf\n", l);
	return 0;
}