K-variance

Very easy

Execution time limit is 1 second

Runtime memory usage limit is 128 megabytes

Consider the variance of the sequence $a_{1}, a_{2}, ..., a_{n}$ as

\frac{\sum _{i = 1}^{n} ( a _{i} - a ˉ ) ^{2}}{n - 1}

where

\overset{a}{ˉ} = \frac{\sum _{i = 1}^{n} a _{i}}{n}

Consider the K-variance as the variance of the consecutive subsequence of length $k$ .

Your task is to calculate all $(n - k + 1)$ K-variances for the given sequence and $k$ .

Formally, the $i$ -th $(1 \leq i \leq n - k + 1)$ K-variance $r_{i}$ is the variance of sequence ${a_{i}, a_{i + 1}, ..., a_{i + k - 1}}$ .

Input

The first line contains two integers $n$ and $k (2 \leq k \leq n \leq 1 0^{5})$ .

The second line contains $n$ integers $a_{1}, a_{2}, ..., a_{n} (∣ a_{i} ∣ \leq 100)$ .

Print $(n - k + 1)$ lines with real numbers $r_{1}, r_{2}, ..., r_{n - k + 1}$ .

The answer is considered correct if its absolute or relative error does not exceed $1 0^{- 4}$ .

Input #1

Answer #1

Input #2

Answer #2

Submissions 57

Acceptance rate 32%