C++ algorithm max_element and min_element

Table of contents

  vector<int> vec = {18, 21, 42, 17, 0, -1, 21, 10, 10};

  auto mx = max_element(begin(vec), end(vec));  // O(N)
  auto mn = min_element(begin(vec), end(vec));  // O(N)

  cout << "Max element is " << *mx << endl;
  cout << "Min element is " << *mn << endl;

Print lambda:

  auto print = [](const auto &vec, const string &msg) {
    for (const auto &e : vec) {
      cout << e << ' ';
    }
    cout << msg << endl;
  };

The std::swap() is a built-in function in C++ STL which swaps the value of any two variables passed to it as parameters.

  print(vec, "original vector");
  std::swap(mn, mx);  // swap iterator value, but not its position
  cout << "Max element is " << *mx << endl;
  cout << "Min element is " << *mn << endl;
  print(vec, "after swap");

The std::iter_swap swaps the values of the elements the given iterators are pointing to.

  std::iter_swap(mn, mx);
  print(vec, "after iter_swap");

Possible output

Max element is 42
Min element is -1
18 21 42 17 0 -1 21 10 10 original vector
Max element is -1
Min element is 42
18 21 42 17 0 -1 21 10 10 after swap
18 21 -1 17 0 42 21 10 10 after iter_swap