The insight: equilibrium means the sum of all coordinates is 0, AND the sum of all coordinates is 0, AND the sum of all coordinates is 0. You check three separate conditions.
You don't need vector math libraries. Loop through the forces, maintaining three running sums: This is a perfect use case for a boolean function. Write This insight transforms a complex-looking problem into a manageable one.
Without it, you might overcomplicate the solution or miss edge cases. Look for this pattern in similar problems. Recognizing it quickly will help you solve problems faster in contests and interviews.