n,k=input().split()
work=list(map(int,input().split()))
l=[0]+work
summ=0
big=0
x=1
y=0
while y<int(n)+1:
if y==int(k):
summ+=l[y]
big+=summ
y+=1
elif y<int(k):
summ+=l[y]
y+=1
else:
summ-=l[x]
x+=1
summ+=l[y]
y+=1
big+=summ
print(big/(int(n)-int(k)+1))
// || जय जय जय बजरंग बली ||
#include <bits/stdc++.h>
using namespace std;
#define ll long long
void solve() {
int n,k;
cin >> n >> k;
vector<double> vc(n);
for(int i=0; i<n; i++) {
cin >> vc[i];
}
int i=0;
double ans = 0.0;
double mx = 0.0;
while(i < k) {
ans += vc[i];
i++;
}
int j=0;
mx += ans;
while(i < n) {
ans = (ans + vc[i] - vc[j]);
mx += ans;
i++;
j++;
}
double deno = (double)(n - k + 1.0);
cout << fixed << setprecision(10) << mx/deno;
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int tc = 1;
//cin >> tc;
while(tc--) {
solve();
}
return 0;
}
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102. Binary Tree Level Order Traversal | 96. Unique Binary Search Trees |
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50. Pow(x, n) | 43. Multiply Strings |
34. Find First and Last Position of Element in Sorted Array | 33. Search in Rotated Sorted Array |
17. Letter Combinations of a Phone Number | 5. Longest Palindromic Substring |
3. Longest Substring Without Repeating Characters | 1312. Minimum Insertion Steps to Make a String Palindrome |
1092. Shortest Common Supersequence | 1044. Longest Duplicate Substring |
1032. Stream of Characters | 987. Vertical Order Traversal of a Binary Tree |
952. Largest Component Size by Common Factor | 212. Word Search II |
174. Dungeon Game | 127. Word Ladder |
123. Best Time to Buy and Sell Stock III | 85. Maximal Rectangle |
84. Largest Rectangle in Histogram | 60. Permutation Sequence |