Galactic Transmission Sequence Solution

Explanation: Step 1: Initialize an empty set to store unique elements and a variable to store the maximum length of the subsequence without duplicates. We start with the first element of the array, which is 3. The set contains [3] and the maximum length is 1. Step 2: Iterate over the rest of the array. When we encounter the element 7, we add it to the set and the maximum length becomes 2. Step 3: When we encounter the element 2, we add it to the set and the maximum length becomes 3. Step 4: When we encounter the element 9, we add it to the set and the maximum length becomes 4. Step 5: When we encounter the element 4, we add it to the set and the maximum length becomes 5. However, we should not consider the last element 4 because it is a duplicate. Therefore, the maximum length is 4.

Explanation: Step 1: Initialize an empty set to store unique elements and a variable to store the maximum length of the subsequence without duplicates. We start with the first element of the array, which is 8. The set contains [8] and the maximum length is 1. Step 2: Iterate over the rest of the array. When we encounter the element 6, we add it to the set and the maximum length becomes 2. Step 3: When we encounter the element 8, we add it to the set but do not increment the maximum length because it is a duplicate. Step 4: When we encounter the element 5, we add it to the set and the maximum length becomes 3. Step 5: When we encounter the element 2, we add it to the set and the maximum length becomes 4.