Function build_tree

test/source/core/unbalanced.cpp:51–97

* @brief Build an unbalanced tree containing all the numbers from 0 to n - 1. */

 * @brief Build an unbalanced tree containing all the numbers from 0 to n - 1.
 */
auto build_tree(int n, double skew) -> std::unique_ptr<tree> {

  REQUIRE(n > 0);
  REQUIRE(skew > 0);
  REQUIRE(skew < 1);

  if (n < 1) {
    return nullptr;
  }

  xoshiro rng{seed, std::random_device{}};

  std::vector<int> vals;

  for (int i = 0; i < n; ++i) {
    vals.push_back(i);
  }

  std::shuffle(vals.begin(), vals.end(), rng);

  std::unique_ptr<tree> root = nullptr;
  std::uniform_real_distribution<double> dist{0, 1};

  for (auto val : vals) {
    if (dist(rng) < skew) {
      root = std::make_unique<tree>(tree{val, std::move(root), nullptr});
    } else {
      root = std::make_unique<tree>(tree{val, nullptr, std::move(root)});
    }
  }

  auto untwist = [&](auto &self, tree &tree) -> void {
    if (dist(rng) < 0.5) {
      std::swap(tree.left, tree.right);
    }
    if (tree.left) {
      self(self, *tree.left);
    }
    if (tree.right) {
      self(self, *tree.right);
    }
  };

  untwist(untwist, *root);

  return root;
}

LF_NOINLINE auto find(tree const &root, int val) -> bool {