# 1000. Minimum Cost to Merge Stones

<https://leetcode.com/problems/minimum-cost-to-merge-stones>

## Description

There are `n` piles of `stones` arranged in a row. The `ith` pile has `stones[i]` stones.

A move consists of merging exactly `k` consecutive piles into one pile, and the cost of this move is equal to the total number of stones in these `k` piles.

Return *the minimum cost to merge all piles of stones into one pile*. If it is impossible, return `-1`.

**Example 1:**

```
**Input:** stones = [3,2,4,1], k = 2
**Output:** 20
**Explanation:** We start with [3, 2, 4, 1].
We merge [3, 2] for a cost of 5, and we are left with [5, 4, 1].
We merge [4, 1] for a cost of 5, and we are left with [5, 5].
We merge [5, 5] for a cost of 10, and we are left with [10].
The total cost was 20, and this is the minimum possible.
```

**Example 2:**

```
**Input:** stones = [3,2,4,1], k = 3
**Output:** -1
**Explanation:** After any merge operation, there are 2 piles left, and we can't merge anymore.  So the task is impossible.
```

**Example 3:**

```
**Input:** stones = [3,5,1,2,6], k = 3
**Output:** 25
**Explanation:** We start with [3, 5, 1, 2, 6].
We merge [5, 1, 2] for a cost of 8, and we are left with [3, 8, 6].
We merge [3, 8, 6] for a cost of 17, and we are left with [17].
The total cost was 25, and this is the minimum possible.
```

**Constraints:**

* `n == stones.length`
* `1 <= n <= 30`
* `1 <= stones[i] <= 100`
* `2 <= k <= 30`

## ac

```java
```


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://jaywin.gitbook.io/leetcode/solutions/1000-minimum-cost-to-merge-stones.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.