881633. Sum Unique Elements
Here is the detailed Markdown blog post for the GeeksforGeeks problem "Sum Unique Elements":
Sum Unique Elements -- 160334
Summary
This problem involves finding the sum of all unique elements in a given array. This is an easy problem that requires basic knowledge of arrays and algorithms.
Detailed Explanation
To solve this problem, we can use a simple algorithm involving a set data structure from the STL library. A set automatically removes duplicate elements, so we can iterate through the array, adding each element to the set, and then find the sum of all elements in the set.
Here is a step-by-step breakdown of the solution:
- Initialize an empty set
unique_elements. - Iterate through the given array.
- For each element in the array, add it to
unique_elementsusing theinsertfunction. - Calculate the sum of all unique elements by iterating through
unique_elementsand adding up their values.
Here is a sample diagram illustrating the process:
+---------------+
| Unique Elements |
+---------------+
|
| Add elements to set
v
+---------------+
| Array: [1, 2, 3, 4, 5, 2, 3] |
+---------------+
^
| Remove duplicates
|
+---------------+
| Unique Elements: [1, 2, 3, 4, 5] |
+---------------+
|
| Calculate sum
v
+---------------+
| Sum: 15 |
+---------------+
The time complexity of this algorithm is O(n log n) due to the use of the set data structure. The space complexity is also O(n), as we are storing each unique element in the set.
Optimized Solutions
Java
import java.util.HashSet;
import java.util.Set;
public class SumUniqueElements {
public static int sumUnique(int[] arr) {
Set<Integer> uniqueElements = new HashSet<>();
for (int num : arr) {
uniqueElements.add(num);
}
int sum = 0;
for (int num : uniqueElements) {
sum += num;
}
return sum;
}
}