How to Find the Unique Elements in an Array in C++? Last Updated : 01 Mar, 2024 Comments Improve Suggest changes Like Article Like Report In C++, an array is a data structure that is used to store multiple values of similar data types in a contiguous memory location. In this article, we will learn how to find the unique elements in an array in C++. Example: Input: array = {1, 2, 1, 2, 2, 3, 4} Output: Unique elements in the array: 1 2 3 4Find the Unique Elements in an Array in C++To find the Unique elements in a std::array in C++, we can iterate through the array and store the array elements in a std::set because the set will store the unique elements of the array and ignore the duplicate values. C++ Program to Find Unique Elements in an ArrayThe below program demonstrates how we can find the unique elements in an array in C++. C++ // C++ Program to illustrate how to find unique elements in // an array #include <iostream> #include <set> #include <vector> using namespace std; // driver code int main() { vector<int> arr = { 1, 2, 1, 2, 2, 3, 4 }; set<int> s; // inserting elements in the set. s.insert(arr.begin(), arr.end()); cout << "Unique elements in the array: "; for (auto it = s.begin(); it != s.end(); ++it) cout << ' ' << *it; return 0; } OutputUnique elements in the array: 1 2 3 4Time Complexity: O(N * log(N)), where N is the number of elements in the set.Auxiliiary Space: O(N) Comment More infoAdvertise with us Next Article How to Find the Unique Elements in an Array in C++? A akshitsaxena2 Follow Improve Article Tags : C++ cpp-array CPP Examples Practice Tags : CPP Similar Reads Remove duplicate elements in an Array using STL in C++ Given an array, the task is to remove the duplicate elements from the array using STL in C++ Examples: Input: arr[] = {2, 2, 2, 2, 2} Output: arr[] = {2} Input: arr[] = {1, 2, 2, 3, 4, 4, 4, 5, 5} Output: arr[] = {1, 2, 3, 4, 5} Approach: This can be done using set in standard template library. Set 2 min read Find the Frequency of Each Element in a Vector in C++ The frequency of an element is number of times it occurred in the vector. In this article, we will learn different methods to find the frequency of each element in a vector in C++.The simplest method to find the frequency of each element in a vector is by iterating the vector and storing the count o 3 min read Elements that occurred only once in the array Given an array arr that has numbers appearing twice or once. 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