Leetcode 2551. Put Marbles in Bags

Partition the array into k contiguous nonempty subarrays where each bag's cost is the sum of its endpoint weights, so the total score equals weights[0]+weights[n-1] plus the sum of the k-1 adjacent pair sums at cut positions. The problem reduces to choosing k-1 cuts (from n-1 adjacent-pair sums) to maximize or minimize their sum, so the answer is the difference between the sum of the largest k-1 and the smallest k-1 adjacent pair sums.