P23145 [AtCoder] Pancakes
提高+
题目描述

Problem Statement

We have a pancake tower which is a pile of N pancakes. Initially, the i-th pancake from the top $(1 \leq i \leq N) has a$ size of A_i. Takahashi, a chef, can do the following operation at most once.

  • Choose integers l and $r (1 \leq l \lt r \leq N)$ and turn the l-th through r-th pancakes upside down, reversing the order.

Find the minimum possible ugliness of the tower after the operation is done (or not), defined below:

the ugliness is the sum of the differences of the sizes of adjacent pancakes;
that is, the value $|A^{\prime}_1 - A^{\prime}_2| + |A^{\prime}_2 - A^{\prime}_3| + \cdots + |A^{\prime}_{N-1} - A^{\prime}_N|$, where $A^{\prime}_i$ is the size of the i-th pancake from the top.

Input

Input is given from Standard Input in the following format:
N
$A_1 A_2 \cdots A_N$

Output

Print the minimum possible ugliness of the tower.

Constraints

  • $2 \leq N \leq 300000$
  • $1 \leq A_i \leq 10^9$
  • All values in input are integers.

Sample Input 1

5
7 14 12 2 6

Sample Output 1

17

If we do the operation choosing l = 2 and r = 5, the pancakes will have the sizes of 7, 6, 2, 12, 14 from top to bottom.
The ugliness here is |7-6| + |6-2| + |2-12| + |12-14| = 1 + 4 + 10 + 2 = 17. This is the minimum value possible; there is no way to achieve less ugliness.

Sample Input 2

3
111 119 999

Sample Output 2

888

In this sample, not doing the operation minimizes the ugliness.
In that case, the pancakes will have the sizes of 111, 119, 999 from top to bottom, for the ugliness of |111-119| + |119-999| = 8 + 880 = 888.

Sample Input 3

6
12 15 3 4 15 7

Sample Output 3

19

If we do the operation choosing l = 3 and r = 5, the pancakes will have the sizes of 12, 15, 15, 4, 3, 7 from top to bottom.
The ugliness here is |12-15| + |15-15| + |15-4| + |4-3| + |3-7| = 3 + 0 + 11 + 1 + 4 = 19, which is the minimum value possible.

Sample Input 4

7
100 800 500 400 900 300 700

Sample Output 4

1800

If we do the operation choosing l = 2 and r = 4, the pancakes will have the sizes of 100, 400, 500, 800, 900, 300, 700 from top to bottom, for the ugliness of 1800.

Sample Input 5

10
535907999 716568837 128214817 851750025 584243029 933841386 159109756 502477913 784673597 603329725

Sample Output 5

2576376600

输入格式

见题面 Input 部分

输出格式

见题面 Output 部分

样例输入
5 7 14 12 2 6
样例输出
17