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Set STL in CPP 👨‍🎓

aryan015

aryan015

Posted on November 22, 2024

Set STL in CPP 👨‍🎓

Introduction

Set is a data structure that only stores unique elements.

Types of Set

There are two types of set in cpp.

  1. Ordered Set - Maintain sorting while insertion
  2. Unordered Set - Insert in random order which makes it fast.

Initialize 

#include <set>
using namespace std;
int main(){
    set<int> iSet;
    unordered_set<int> uSet;
    iSet.insert(10);
    uSet.insert(10);
}
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Check for an element 

if (iSet.find(20) != iSet.end()) {
    cout << "20 is in the set" << endl;
}
if (uSet.find(20) != uSet.end()) {
    cout << "20 is in the set" << endl;
}
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Erase an element 

iSet.erase(20);
uSet.erase(20);
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Iterate over an element

Iteration is same in ordered and Unordered Set

for (auto it = iSet.begin(); it != iSet.end(); ++it) {
    std::cout << *it << " ";
}
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Get the size 

std::cout << "Size: " << iSet.size() << std::endl;
std::cout << "Unordered Size: " << uSet.size() << std::endl;
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Clear the set 

iSet.clear();
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Difference Between Ordered and Unordered set

Feature std::set std::unordered_set
Order Stores elements in sorted order No particular order
Time Complexity O(log n) for insert, delete, search O(1) average for insert, delete, search
Duplicates Not allowed Not allowed
Use Case When sorting is needed When fast operations are needed

Application

  1. Removing duplicates in an array
  2. Set Operations
💖 💪 🙅 🚩
aryan015
aryan015

Posted on November 22, 2024

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