10496: ABC107 —— C - Candles
[Creator : ]
Description
There are $N$ candles placed on a number line. The $i$-th candle from the left is placed on coordinate $x_i$. Here, $x_1 < x_2 < ... < x_N$ holds.
Initially, no candles are burning. Snuke decides to light $K$ of the $N$ candles.
Now, he is at coordinate $0$. He can move left and right along the line with speed $1$. He can also light a candle when he is at the same position as the candle, in negligible time.
Find the minimum time required to light $K$ candles.
Initially, no candles are burning. Snuke decides to light $K$ of the $N$ candles.
Now, he is at coordinate $0$. He can move left and right along the line with speed $1$. He can also light a candle when he is at the same position as the candle, in negligible time.
Find the minimum time required to light $K$ candles.
Input
Input is given from Standard Input in the following format:
```
$N$ $K$
$x_1$ $x_2$ $...$ $x_N$
```
```
$N$ $K$
$x_1$ $x_2$ $...$ $x_N$
```
Output
Print the minimum time required to light $K$ candles.
Constraints
- $1 \leq N \leq 10^5$
- $1 \leq K \leq N$
- $x_i$ is an integer.
- $|x_i| \leq 10^8$
- $x_1<x_2 < ... < x_N$
- $1 \leq K \leq N$
- $x_i$ is an integer.
- $|x_i| \leq 10^8$
- $x_1<x_2 < ... < x_N$
Sample 1 Input
5 3
-30 -10 10 20 50
Sample 1 Output
40
He should move and light candles as follows:
- Move from coordinate 0 to -10.
- Light the second candle from the left.
- Move from coordinate -10 to 10.
- Light the third candle from the left.
- Move from coordinate 10 to 20.
- Light the fourth candle from the left.
Sample 2 Input
3 2
10 20 30
Sample 2 Output
20
Sample 3 Input
1 1
0
Sample 3 Output
0
There may be a candle placed at coordinate 0.
8 5
-9 -7 -4 -3 1 2 3 4
10