在一條線狀的草地上，有N叢草。你可以把他視為數線上的N個數(1 <= N <= 1,000)，這些數分別在一些整數點上。

Bessie是一隻牛，從位置L出發，想要把所有這些草吃完。定義一株草”不新鮮度”是從開始到Bessie吃到該株草所過的時間。如今Bessie希望在吃到這些草的同時，吃所有草的”不新鮮度”總和可以最小。請找出最小的”不新鮮度”總和是多少。

(原文)

A long, linear field has N (1 <= N <= 1,000) clumps of grass at unique integer locations on what will be treated as a number line. Think of the clumps as points on the number line.

Bessie starts at some specified integer location L on the number line (1 <= L <= 1,000,000) and traverses the number line in the two possible directions (sometimes reversing her direction) in order to reach and eat all the clumps. She moves at a constant speed (one unit of distance in one unit of time), and eats a clump instantly

when she encounters it.

Clumps that aren't eaten for a while get stale. We say the ``staleness'' of a clump is the amount of time that elapses from when Bessie starts moving until she eats a clump. Bessie wants to minimize the total staleness of all the clumps she eats.

Find the minimum total staleness that Bessie can achieve while eating all the clumps.

第一行有兩個整數N和L，代表有幾株草，以及開始的位置(1 <= L <= 1,000,000)

接下來N行每行有一個整數P，代表某株草在數線上的位置。

(原文)

* Line 1 : Two space-separated integers: N and L.

* Lines 2..N+1: Each line contains a single integer giving the position P of a clump (1 <= P <= 1,000,000).

請輸出一個整數，代表最小的”不新鮮度”總和。

(原文)

* Line 1: A single integer: the minimum total staleness Bessie can achieve while eating all the clumps.

4 10

1

9

11

19

1

9

11

19

44

對於範例I/O, 可以這麼做:

* start at position 10 at time 0

* move to position 9, arriving at time 1

* move to position 11, arriving at time 3

* move to position 19, arriving at time 11

* move to position 1, arriving at time 29

giving her a total staleness of 1+3+11+29 = 44. There are other routes with the same total staleness, but no route with a smaller one.

原TIOJ1090 / USACO Gold Demo, 2005 Nov。Translation/Problem Setter: kelvin。

No. | Testdata Range | Score |
---|---|---|

1 | 0 | 10 |

2 | 1 | 10 |

3 | 2 | 10 |

4 | 3 | 10 |

5 | 4 | 10 |

6 | 5 | 10 |

7 | 6 | 10 |

8 | 7 | 10 |

9 | 8 | 10 |

10 | 9 | 10 |