Candles

AtCoder

IDarc101_a

Time2000ms

Memory256MB

Difficulty—

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. ## Constraints * $1 \leq N \leq 10^5$ * $1 \leq K \leq N$ * $x_i$ is an integer. * $|x_i| \leq 10^8$ * $x_1 < x_2 < ... < x_N$ ## Input Input is given from Standard Input in the following format: $N$ $K$ $x_1$ $x_2$ $...$ $x_N$ [samples]

Samples

Input #1

5 3
-30 -10 10 20 50

Output #1

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.

Input #2

3 2
10 20 30

Output #2

Input #3

1 1
0

Output #3

0

*   There may be a candle placed at coordinate $0$.

Input #4

8 5
-9 -7 -4 -3 1 2 3 4

Output #4

API Response (JSON)

{
  "problem": {
    "name": "Candles",
    "description": {
      "content": "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 ",
      "description_type": "Markdown"
    },
    "platform": "AtCoder",
    "limit": {
      "time_limit": 2000,
      "memory_limit": 262144
    },
    "difficulty": "None",
    "is_remote": true,
    "is_sync": true,
    "sync_url": null,
    "sign": "arc101_a"
  },
  "statements": [
    {
      "statement_type": "Markdown",
      "content": "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.\nInitially, no candles are burning. Snuke decides to ...",
      "is_translate": false,
      "language": "English"
    }
  ]
}

Full JSON Raw Segments