set lower_bound() in C++

lower_bound(): This is a build-in function in STL. This function finds the beginning of a subsequence matching given key. This function returns an iterator pointing to the first element

equal to or greater than key, or end(). 

This function returns the first element of a subsequence of elements that match the given key. If unsuccessful it returns an iterator pointing to the first element that has a greater value than the given key or end() if no such element exists.

Parameters: One parameter is required for this function.

 __x – Key to being located. 

Syntax:

set<data_type>::iterator it = st.lower_bound(__x)

For Example:

st = {1,19,5,2}

st.lower_bound(3) = > It returns iterator pointing to 5.

Approach

C++

#include <bits/stdc++.h>
using namespace std;

int main()
{
    set<int> st;
    st.insert({1, 19, 5, 2});

    set<int>::iterator it = st.lower_bound(3);

    cout << *it << "\n";

    return 0;
}