1899. merge triplets to form target triplet

A triplet is an array of three integers. You are given a 2D integer array triplets, where triplets[i] = [ai, bi, ci] describes the ith triplet. You are also given an integer array target = [x, y, z] that describes the triplet you want to obtain.

To obtain target, you may apply the following operation on triplets any number of times (possibly zero):

• Choose two indices (0-indexed) i and j (i != j) and update triplets[j] to become [max(ai, aj), max(bi, bj), max(ci, cj)].
  • For example, if triplets[i] = [2, 5, 3] and triplets[j] = [1, 7, 5], triplets[j] will be updated to [max(2, 1), max(5, 7), max(3, 5)] = [2, 7, 5].

Return true if it is possible to obtain the target triplet [x, y, z] as an element of triplets, or false otherwise.

solution

We note that if a triplet has a value that’s too big for target, we can’t do any operations with it because we’ll overshoot the value in target.

If there’s a triplet that has a value that matches the value in target, then we know we can use it along with some other value that doesn’t violate the point mentioned above.

class Solution:
	def mergeTriplets(self, triplets: List[List[int]], target: List[int]) -> bool:
		tx, ty, tz = target
		acc = [0, 0, 0]
 
		for x, y, z in triplets:
			if [x,y,z] == target:
				return True
 
			if x <= tx and y <= ty and z <= tz:
				acc = [max(i, j) for i, j in zip(acc, [x,y,z])]
 
return acc == target