Certainly! Here is a test case generator for the provided problem statement:

```python
import random

def tcgen():
    # Constraints
    MAX_N = 200
    MAX_A = 10**18
    MAX_K = 10**18
    
    # Generate random values within the constraints
    N = random.randint(1, MAX_N)
    K = random.randint(1, MAX_K)
    A = [random.randint(1, MAX_A) for _ in range(N)]
    
    return N, K, A

# Printing generated test case for demonstration
N, K, A = tcgen()
print(N)
print(K)
print(" ".join(map(str, A)))
```

### Explanation:
- **N**: The number of integers on the blackboard is chosen randomly between 1 and 200.
- **K**: The maximum number of operations is chosen randomly between 1 and \(10^{18}\).
- **A**: The list of integers (each between 1 and \(10^{18}\)) written on the blackboard is generated.

This generator will provide random test cases that adhere to the constraints specified in the problem statement. You can run this script to generate a random test case and then use it for further testing of your solution.