Codeforces Round #494 (Div. 3) C. Intense Heat
The heat during the last few days has been really intense. Scientists from all over the Berland study how the temperatures and weather change, and they claim that this summer is abnormally hot. But any scientific claim sounds a lot more reasonable if there are some numbers involved, so they have decided to actually calculate some value which would represent how high the temperatures are.
Mathematicians of Berland State University came up with a special heat intensity value. This value is calculated as follows:
Suppose we want to analyze the segment of nn consecutive days. We have measured the temperatures during these nn days; the temperature during ii-th day equals aiai.
We denote the average temperature of a segment of some consecutive days as the arithmetic mean of the temperature measures during this segment of days. So, if we want to analyze the average temperature from day xx to day yy, we calculate it as y∑i=xaiy−x+1∑i=xyaiy−x+1 (note that division is performed without any rounding). The heat intensity value is the maximum of average temperatures over all segments of not less than kkconsecutive days. For example, if analyzing the measures [3,4,1,2][3,4,1,2] and k=3k=3, we are interested in segments [3,4,1][3,4,1], [4,1,2][4,1,2] and [3,4,1,2][3,4,1,2] (we want to find the maximum value of average temperature over these segments).
You have been hired by Berland State University to write a program that would compute the heat intensity value of a given period of days. Are you up to this task?
The first line contains two integers nn and kk (1≤k≤n≤50001≤k≤n≤5000) — the number of days in the given period, and the minimum number of days in a segment we consider when calculating heat intensity value, respectively.
The second line contains nn integers a1a1, a2a2, ..., anan (1≤ai≤50001≤ai≤5000) — the temperature measures during given nn days.
Print one real number — the heat intensity value, i. e., the maximum of average temperatures over all segments of not less than kkconsecutive days.
Your answer will be considered correct if the following condition holds: |res−res0|<10−6|res−res0|<10−6, where resres is your answer, and res0res0 is the answer given by the jury's solution.
4 3
3 4 1 2
2.666666666666667
#include<cstdio> #include<cstring> #include<algorithm> #include<iostream> #include<string> #include<vector> #include<stack> #include<bitset> #include<cstdlib> #include<cmath> #include<set> #include<list> #include<deque> #include<map> #include<queue> #define INF 0x3f3f3f3f; #define ll long long ll gcd(ll p,ll q) { return q==0?p:gcd(q,p%q); } using namespace std; const int manx=1e5+10; double n,k,a[5010],sum[5000],ans; int main() { cin>>n>>k; for(int i=1; i<=n; i++) cin>>a[i]; sum[0]=0; for(int i=1; i<=n; i++) sum[i]=sum[i-1]+a[i]; for(int i=k; i<=n; i++)///枚举长度 for(int j=i; j<=n; j++) ans=max(ans,(sum[j]-sum[j-i])/i); printf("%.15lf\n",ans); return 0; }
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