Problem
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]
andtriplets[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**.
Example 1:
Input: triplets = [[2,5,3],[1,8,4],[1,7,5]], target = [2,7,5]
Output: true
Explanation: Perform the following operations:
- Choose the first and last triplets [[2,5,3],[1,8,4],[1,7,5]]. Update the last triplet to be [max(2,1), max(5,7), max(3,5)] = [2,7,5]. triplets = [[2,5,3],[1,8,4],[2,7,5]]
The target triplet [2,7,5] is now an element of triplets.
Example 2:
Input: triplets = [[3,4,5],[4,5,6]], target = [3,2,5]
Output: false
Explanation: It is impossible to have [3,2,5] as an element because there is no 2 in any of the triplets.
Example 3:
Input: triplets = [[2,5,3],[2,3,4],[1,2,5],[5,2,3]], target = [5,5,5]
Output: true
Explanation: Perform the following operations:
- Choose the first and third triplets [[2,5,3],[2,3,4],[1,2,5],[5,2,3]]. Update the third triplet to be [max(2,1), max(5,2), max(3,5)] = [2,5,5]. triplets = [[2,5,3],[2,3,4],[2,5,5],[5,2,3]].
- Choose the third and fourth triplets [[2,5,3],[2,3,4],[2,5,5],[5,2,3]]. Update the fourth triplet to be [max(2,5), max(5,2), max(5,3)] = [5,5,5]. triplets = [[2,5,3],[2,3,4],[2,5,5],[5,5,5]].
The target triplet [5,5,5] is now an element of triplets.
Constraints:
1 <= triplets.length <= 10^5
triplets[i].length == target.length == 3
1 <= ai, bi, ci, x, y, z <= 1000
Solution (Java)
class Solution {
public boolean mergeTriplets(int[][] triplets, int[] target) {
boolean one = false;
boolean two = false;
boolean three = false;
for (int[] triplet : triplets) {
if (!one
&& triplet[0] == target[0]
&& triplet[1] <= target[1]
&& triplet[2] <= target[2]) {
one = true;
}
if (!two
&& triplet[0] <= target[0]
&& triplet[1] == target[1]
&& triplet[2] <= target[2]) {
two = true;
}
if (!three
&& triplet[0] <= target[0]
&& triplet[1] <= target[1]
&& triplet[2] == target[2]) {
three = true;
}
if (one && two && three) {
return true;
}
}
return false;
}
}
Explain:
nope.
Complexity:
- Time complexity : O(n).
- Space complexity : O(n).