reverse function in c++ coplexity code example

Example 1: c++ reverse vector

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

int main()
{
    vector<int> nums{4,1,2,1,2};

    reverse(nums.begin(), nums.end());
    return 0;
}

Example 2: std::reverse

std::vector<int> v{1,2,3};
    std::reverse(std::begin(v), std::end(v));