How to solve: Merge Two Dictionaries with Value Sums?

Question

Accepted Answer

To merge dictionaries and sum values for duplicate keys:
1. Create a copy of the first dictionary to avoid mutating the original input: `res = d1.copy()`.
2. Loop over the key-value pairs in the second dictionary: `for k, v in d2.items()`.
3. Use the dict's `get(key, default)` method to add the values together: `res[k] = res.get(k, 0) + v`.