Set - Store Unique Elements
Medium
C++
STL
61 views
Problem Statement
Set automatically keeps only unique elements, sorted.
Real Life: Collection of unique items, no duplicates.
Real Life: Collection of unique items, no duplicates.
Input Format
An integer n (number of elements)
Then n integers (may contain duplicates).
Then n integers (may contain duplicates).
Output Format
All unique elements printed in sorted order.
Example
6 5 2 3 5 2 4
2 3 4 5
Constraints
• n ≥ 1
• Elements can repeat
• Order is automatically sorted
• Elements can repeat
• Order is automatically sorted
Concept Explanation
A set stores only unique values.
If a duplicate value is inserted, it is ignored automatically.
All elements are kept in sorted order.
This is useful for maintaining a collection of unique items,
like unique IDs, roll numbers, or product codes.
If a duplicate value is inserted, it is ignored automatically.
All elements are kept in sorted order.
This is useful for maintaining a collection of unique items,
like unique IDs, roll numbers, or product codes.
Step-by-Step Explanation
1.Create a set.
2.Read elements one by one.
3.Insert each element into the set using insert().
4.If an element already exists:
• Set ignores it.
5.Set automatically sorts all stored elements.
6.Traverse the set using iterator or loop.
7.Print all elements.
2.Read elements one by one.
3.Insert each element into the set using insert().
4.If an element already exists:
• Set ignores it.
5.Set automatically sorts all stored elements.
6.Traverse the set using iterator or loop.
7.Print all elements.
Concept Explanation
A set stores only unique values.
If a duplicate value is inserted, it is ignored automatically.
All elements are kept in sorted order.
This is useful for maintaining a collection of unique items,
like unique IDs, roll numbers, or product codes.
If a duplicate value is inserted, it is ignored automatically.
All elements are kept in sorted order.
This is useful for maintaining a collection of unique items,
like unique IDs, roll numbers, or product codes.
Step-by-Step Explanation
1.Create a set.
2.Read elements one by one.
3.Insert each element into the set using insert().
4.If an element already exists:
• Set ignores it.
5.Set automatically sorts all stored elements.
6.Traverse the set using iterator or loop.
7.Print all elements.
2.Read elements one by one.
3.Insert each element into the set using insert().
4.If an element already exists:
• Set ignores it.
5.Set automatically sorts all stored elements.
6.Traverse the set using iterator or loop.
7.Print all elements.
Input / Output Format
Input Format
An integer n (number of elements)
Then n integers (may contain duplicates).
Then n integers (may contain duplicates).
Output Format
All unique elements printed in sorted order.
Constraints
• n ≥ 1
• Elements can repeat
• Order is automatically sorted
• Elements can repeat
• Order is automatically sorted
Examples
Input:
6
5 2 3 5 2 4
Output:
2 3 4 5
Example Solution (Public)
void stl_q7_set() {
set<int> uniqueNumbers;
uniqueNumbers.insert(30);
uniqueNumbers.insert(10);
uniqueNumbers.insert(20);
uniqueNumbers.insert(10); // Duplicate, will be ignored
cout << "Unique numbers (sorted): ";
for(int num : uniqueNumbers) {
cout << num << " ";
}
cout << endl;
cout << "Size: " << uniqueNumbers.size() << endl;
}
Official Solution Code
void stl_q7_set() {
set<int> uniqueNumbers;
uniqueNumbers.insert(30);
uniqueNumbers.insert(10);
uniqueNumbers.insert(20);
uniqueNumbers.insert(10); // Duplicate, will be ignored
cout << "Unique numbers (sorted): ";
for(int num : uniqueNumbers) {
cout << num << " ";
}
cout << endl;
cout << "Size: " << uniqueNumbers.size() << endl;
}
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