C++ 프로그래밍에서 함수 성능을 최적화하는 방법은 무엇입니까?

int sum(const std::vector<int>& numbers) {
  int sum = 0;
  for (auto number : numbers) {
    sum += number;
  }
  return sum;
}

// 内存池
class MemoryPool {
public:
  MemoryPool() : m_allocations(0) {}

  void* allocate(size_t size) {
    m_allocations++;
    return malloc(size);
  }

  void deallocate(void* ptr) {
    free(ptr);
    m_allocations--;
  }

  size_t allocations() const { return m_allocations; }

private:
  size_t m_allocations;
};

// 缓存器
class Cache {
public:
  void set(const std::string& key, const std::string& value) {
    m_cache[key] = value;
  }

  std::string get(const std::string& key) {
    auto it = m_cache.find(key);
    return it != m_cache.end() ? it->second : "";
  }

private:
  std::unordered_map<std::string, std::string> m_cache;
};

// 优化后的求和函数
int sum_optimized(const std::vector<int>& numbers) {
  // 分配内存池
  MemoryPool pool;
  std::vector<int> numbers_cached;
  numbers_cached.reserve(numbers.size());

  // 缓存数字
  for (auto number : numbers) {
    numbers_cached.push_back(number);
  }

  // 使用缓存的数字求和
  int sum = 0;
  for (auto number : numbers_cached) {
    sum += number;
  }

  // 释放内存池
  pool.deallocate(&numbers_cached[0]);

  return sum;
}