Iterators.cpp

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

/*
Input Iterators
    (*, ->, ++, ==, !=)
Output Iterators
    (*, ++)
Forward Iterators
    (*, ->, ++, ==, !=)
    forward_list
Bidirectional Iteartors
    (*, ->, ++, --, ==, !=)
    list, set, multiset, map, multimap
Random-Access Iterators
    (*, ->, [], ++, --, +, -, ==, !=, <, >, <=, >=)
    array, vector, deque, string
*/
void solve() {
    vector<int> v = {1, 2, 3, 4, 5, 6};

    vector<int>::iterator it_begin = v.begin();
    vector<int>::iterator it_end = v.end();
    vector<int>::reverse_iterator it_rbegin = v.rbegin();
    vector<int>::reverse_iterator it_rend = v.rend();

    // Bidirectional -> O(n), Random-Access -> O(1)
    // distance(it_first, it_last), can be negative for random-access iterators
    // next(it), next(it, n)
    // prev(it), prev(it, n)
    // advance(it, n)

    cout << distance(it_begin, it_end) << '\n';
    cout << distance(it_end, it_begin) << '\n';

    cout << *next(it_begin, 2) << '\n';
    cout << *prev(it_end, 2) << '\n';
    cout << *next(it_rbegin) << '\n';
    cout << *prev(it_rend) << '\n';

    advance(it_begin, 4);
    cout << *it_begin << '\n';
}

int32_t main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    int t = 1;
    //cin >> t;

    while (t--) {
        solve();
    }

    return 0;
}