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