Package g0901_1000.s1000_minimum_cost_to_merge_stones

Class Solution

java.lang.Object
g0901_1000.s1000_minimum_cost_to_merge_stones.Solution
public class Solution extends java.lang.Object
1000 - Minimum Cost to Merge Stones.

Hard

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

  • Constructor Summary

    Constructors
    Constructor
    Description
    Solution()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    int
    mergeStones(int[] stones, int k)
     

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • Solution

      public Solution()

  • Method Details

    • mergeStones

      public int mergeStones(int[] stones, int k)