Find Maximum and Minimum element in a Set in C++ STL

Given a Set, the task is to find the maximum and minimum element of this set in C++ STL.

Examples:

Input: set={1, 6, 15, 10, 5}
Output: max = 15, min = 1

Input: set={10, 20, 30, 40, 50, 60}
Output: max = 60, min = 10

Using set.begin() and set.end() methods

Approach: Elements in a set are stored in sorted order. So the minimum element of the set will reside in the first element and the maximum element in the last element. Therefore, this first and last element can be fetched with the help of set.begin() and set.end() methods respectively.

Program:

#include <bits/stdc++.h> 
using namespace std; 
  
// Function to print the set 
void printSet(set<int> my_set) 
{ 
  
    // Print the set 
    cout << "Set: "; 
    for (auto i : my_set) 
        cout << i << " "; 
  
    cout << '\n'; 
} 
  
// Function to find the maximum element 
int findMax(set<int> my_set) 
{ 
  
    // Get the maximum element 
    int max_element; 
    if (!my_set.empty()) 
        max_element = *(my_set.rbegin()); 
  
    // return the maximum element 
    return max_element; 
} 
  
// Function to find the minimum element 
int findMin(set<int> my_set) 
{ 
  
    // Get the minimum element 
    int min_element; 
    if (!my_set.empty()) 
        min_element = *my_set.begin(); 
  
    // return the minimum element 
    return min_element; 
} 
  
int main() 
{ 
  
    // Get the set 
    set<int> my_set; 
  
    // Add the elements in the set 
    my_set.insert(1); 
    my_set.insert(6); 
    my_set.insert(15); 
    my_set.insert(10); 
    my_set.insert(5); 
  
    // Print the set 
    printSet(my_set); 
  
    // Get the minimum element 
    cout << "Minimum element: "
         << findMin(my_set) 
         << endl; 
  
    // Get the maximum element 
    cout << "Maximum element: "
         << findMax(my_set) 
         << endl; 
} 

Output:

Set: 1 5 6 10 15 
Minimum element: 1
Maximum element: 15

Using set.rbegin() and set.rend() methods

Program:

#include <bits/stdc++.h> 
using namespace std; 
  
// Function to print the set 
void printSet(set<int> my_set) 
{ 
  
    // Print the set 
    cout << "Set: "; 
    for (auto i : my_set) 
        cout << i << " "; 
  
    cout << '\n'; 
} 
  
// Function to find the maximum element 
int findMax(set<int> my_set) 
{ 
  
    // Get the maximum element 
    int max_element; 
    if (!my_set.empty()) 
        max_element = *my_set.rbegin(); 
  
    // return the maximum element 
    return max_element; 
} 
  
// Function to find the minimum element 
int findMin(set<int> my_set) 
{ 
  
    // Get the minimum element 
    int min_element; 
    if (!my_set.empty()) 
        min_element = *(--my_set.rend()); 
  
    // return the minimum element 
    return min_element; 
} 
  
int main() 
{ 
  
    // Get the set 
    set<int> my_set; 
  
    // Add the elements in the set 
    my_set.insert(1); 
    my_set.insert(6); 
    my_set.insert(15); 
    my_set.insert(10); 
    my_set.insert(5); 
  
    // Print the set 
    printSet(my_set); 
  
    // Get the minimum element 
    cout << "Minimum element: "
         << findMin(my_set) 
         << endl; 
  
    // Get the maximum element 
    cout << "Maximum element: "
         << findMax(my_set) 
         << endl; 
} 

Output:

Set: 1 5 6 10 15 
Minimum element: 1
Maximum element: 15

My Personal Notes

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