Problem7286--AtCoder Educational DP Contest —— N - Slimes

7286: AtCoder Educational DP Contest —— N - Slimes

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Time Limit : 1.000 sec  Memory Limit : 256 MiB

Description

There are $N$ slimes lining up in a row. Initially, the $i$-th slime from the left has a size of $a_i$.
Taro is trying to combine all the slimes into a larger slime. He will perform the following operation repeatedly until there is only one slime:
  • Choose two adjacent slimes, and combine them into a new slime. The new slime has a size of $x + y$, where $x$ and $y$ are the sizes of the slimes before combining them. Here, a cost of $x + y$ is incurred. The positional relationship of the slimes does not change while combining slimes.
Find the minimum possible total cost incurred.

Input

Input is given from Standard Input in the following format:
$N$
$a_1\ a_2\ \ldots\ a_N$

Output

Print the minimum possible total cost incurred.

Constraints

All values in input are integers.
$2 \leq N \leq 400$
$1 \leq a_i \leq 10^9$

Sample 1 Input

4
10 20 30 40

Sample 1 Output

190
Taro should do as follows (slimes being combined are shown in bold):
  • (1020, 30, 40) → (30, 30, 40)
  • (3030, 40) → (60, 40)
  • (6040) → (100)

Sample 2 Input

5
10 10 10 10 10

Sample 2 Output

120

Taro should do, for example, as follows:

  • (1010, 10, 10, 10) → (20, 10, 10, 10)
  • (20, 1010, 10) → (20, 20, 10)
  • (20, 2010) → (20, 30)
  • (2030) → (50)

Sample 3 Input

3
1000000000 1000000000 1000000000

Sample 3 Output

5000000000

6
7 6 8 6 1 1

68

Taro should do, for example, as follows:

  • (7, 6, 8, 6, 11) → (7, 6, 8, 6, 2)
  • (7, 6, 8, 62) → (7, 6, 8, 8)
  • (76, 8, 8) → (13, 8, 8)
  • (13, 88) → (13, 16)
  • (1316) → (29)

Source/Category