Collecting Balls (Easy Version)

AtCoder

IDabc074_b

Time2000ms

Memory256MB

Difficulty—

There are $N$ balls in the $xy$\-plane. The coordinates of the $i$\-th of them is $(x_i, i)$. Thus, we have one ball on each of the $N$ lines $y = 1$, $y = 2$, $...$, $y = N$. In order to collect these balls, Snuke prepared $2N$ robots, $N$ of type A and $N$ of type B. Then, he placed the $i$\-th type-A robot at coordinates $(0, i)$, and the $i$\-th type-B robot at coordinates $(K, i)$. Thus, now we have one type-A robot and one type-B robot on each of the $N$ lines $y = 1$, $y = 2$, $...$, $y = N$. When activated, each type of robot will operate as follows. * When a type-A robot is activated at coordinates $(0, a)$, it will move to the position of the ball on the line $y = a$, collect the ball, move back to its original position $(0, a)$ and deactivate itself. If there is no such ball, it will just deactivate itself without doing anything. * When a type-B robot is activated at coordinates $(K, b)$, it will move to the position of the ball on the line $y = b$, collect the ball, move back to its original position $(K, b)$ and deactivate itself. If there is no such ball, it will just deactivate itself without doing anything. Snuke will activate some of the $2N$ robots to collect all of the balls. Find the minimum possible total distance covered by robots. ## Constraints * $1 \leq N \leq 100$ * $1 \leq K \leq 100$ * $0 < x_i < K$ * All input values are integers. ## Inputs Input is given from Standard Input in the following format: $N$ $K$ $x_1$ $x_2$ $...$ $x_N$ [samples]

Samples

Input #1

1
10
2

Output #1

4

There are just one ball, one type-A robot and one type-B robot.
If the type-A robot is used to collect the ball, the distance from the robot to the ball is $2$, and the distance from the ball to the original position of the robot is also $2$, for a total distance of $4$.
Similarly, if the type-B robot is used, the total distance covered will be $16$.
Thus, the total distance covered will be minimized when the type-A robot is used. The output should be $4$.

Input #2

2
9
3 6

Output #2

12

The total distance covered will be minimized when the first ball is collected by the type-A robot, and the second ball by the type-B robot.

Input #3

5
20
11 12 9 17 12

Output #3

API Response (JSON)

{
  "problem": {
    "name": "Collecting Balls (Easy Version)",
    "description": {
      "content": "There are $N$ balls in the $xy$\\-plane. The coordinates of the $i$\\-th of them is $(x_i, i)$. Thus, we have one ball on each of the $N$ lines $y = 1$, $y = 2$, $...$, $y = N$. In order to collect thes",
      "description_type": "Markdown"
    },
    "platform": "AtCoder",
    "limit": {
      "time_limit": 2000,
      "memory_limit": 262144
    },
    "difficulty": "None",
    "is_remote": true,
    "is_sync": true,
    "sync_url": null,
    "sign": "abc074_b"
  },
  "statements": [
    {
      "statement_type": "Markdown",
      "content": "There are $N$ balls in the $xy$\\-plane. The coordinates of the $i$\\-th of them is $(x_i, i)$. Thus, we have one ball on each of the $N$ lines $y = 1$, $y = 2$, $...$, $y = N$.\nIn order to collect thes...",
      "is_translate": false,
      "language": "English"
    }
  ]
}

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