3560. Find Minimum Log Transportation Cost

You are given integers n, m, and k.

There are two logs of lengths n and m units, which need to be transported in three trucks where each truck can carry one log with length at most k units.

You may cut the logs into smaller pieces, where the cost of cutting a log of length x into logs of length len1 and len2 is cost = len1 * len2 such that len1 + len2 = x.

Return the minimum total cost to distribute the logs onto the trucks. If the logs don’t need to be cut, the total cost is 0.

func minCuttingCost(n, m, k int) int64 {
	query := func(n, k int64) int64 {
		if n <= k {
			return 0
		}
		return k * (n - k)
	}
	kn := int64(k)
	return query(int64(n), kn) + query(int64(m), kn)
}