Unique Element Report

Easy

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Problem statement

You are given a list of N integers which may contain duplicate values. Your task is to analyze this list and produce a report containing two key pieces of information:

1) The total count of unique (distinct) elements in the list.

2) A sorted list of these unique elements in non-decreasing order.

Detailed explanation ( Input/output format, Notes, Images )

Input Format:

The first line of input contains an integer 'N', the number of elements in the list.

The second line contains 'N' space-separated integers, representing the list of numbers.

Output Format:

The first line of output must be a single integer representing the count of unique elements.

The second line of output must contain the unique elements, sorted in non-decreasing order and separated by single spaces.

Note:

The most efficient way to solve this is to use a data structure that automatically handles uniqueness, such as a Set or a Hash Set.

Sample Input 1:

6
1 22 11 22 5 6

Sample Output 1:

5
1 5 6 11 22

Explanation for Sample 1:

The unique elements in the list `{1, 22, 11, 22, 5, 6}` are `{1, 5, 6, 11, 22}`.
The count of these unique elements is 5.
When sorted, the list of unique elements is `{1, 5, 6, 11, 22}`.

Sample Input 2:

5
5 4 3 2 1

Sample Output 2:

5
1 2 3 4 5

Explanation for Sample 2:

All elements are already unique. The count is 5.
The sorted list of unique elements is `{1, 2, 3, 4, 5}`.

Expected Time Complexity:

The expected time complexity is O(N logN).

Constraints:

1 <= N <= 10^5
-10^9 <= list element <= 10^9

Time limit: 1 sec

Approaches (1)

Approach 1

Unique Element Report

Time Complexity

Space Complexity

(100% EXP penalty)

Unique Element Report

Console