You are given a code snippet that measures the execution time of two different sections of code: `times_topk_join_a` and `times_topk_join_b`. The execution time of `times_topk_join_a` is stored as a list of floating-point numbers. The variable `times_topk_join_b` is also a list of floating-point numbers that stores the execution time of `times_topk_join_b`. Additionally, the code snippet stores the length of `number_of_valid_lines` in two different lists: `number_of_valid_lines_a` and `number_of_valid_lines_b`. 

Your task is to complete the following two functions:

1. `calculate_average_time(times: List[float]) -> float`: This function takes a list of floating-point numbers `times` as a parameter and returns the average time calculated by summing all the values in the list and dividing it by the number of elements.

2. `compare_execution_times(times_a: List[float], times_b: List[float]) -> str`: This function takes two lists of floating-point numbers `times_a` and `times_b` as parameters. It compares the average execution time of `times_a` and `times_b` using the `calculate_average_time` function. If the average execution time of `times_a` is less than that of `times_b`, it returns the string "times_a is faster". If the average execution time of `times_a` is greater than that of `times_b`, it returns the string "times_b is faster". If both are equal, it returns the string "Both have the same average time".

You can assume that the input lists are non-empty.
user
Sure, I'd be happy to help you with this. Here's how you can define these functions in Python:

```python
def calculate_average_time(times: List[float]) -> float:
    return sum(times) / len(times)

def compare_execution_times(times_a: List[float], times_b: List[float]) -> str:
    avg_a = calculate_average_time(times_a)
    avg_b = calculate_average_time(times_b)

    if avg_a < avg_b:
        return "times_a is faster"
    elif avg_a > avg_b:
        return "times_b is faster"
    else:
        return "Both have the same average time"
```

Note that `List` is a built-in data type in Python, so you don't need to specify it when defining a list parameter. Also, the `return` statement in `calculate_average_time` is not needed since it only returns the calculated value. However, I've kept it for clarity.
assistant
You are given a code snippet that measures the execution time of two different sections of code: `times_topk_join_a` and `times_topk_join_b`. The execution time of `times_topk_join_a` is stored as a list of floating-point numbers. The variable `times_topk_join_b` is also a list of floating-point numbers that stores the execution time of `times_topk_join_b`. Additionally, the code snippet stores the length of `number_of_valid_lines` in two different lists: `number_of_valid_lines_a` and `number_of_valid_lines_b`. 

Your task is to complete the following two functions:

1. `calculate_average_time(times: List[float]) -> float`: This function takes a list of floating-point numbers `times` as a parameter and returns the average time calculated by summing all the values in the list and dividing it by the number of elements.

2. `compare_execution_times(times_a: List[float], times_b: List[float]) -> str`: This function takes two lists of floating-point numbers `times_a` and `times_b` as parameters. It compares the average execution time of `times_a` and `times_b` using the `calculate_average_time` function. If the average execution time of `times_a` is less than that of `times_b`, it returns the string "times_a is faster". If the average execution time of `times_a` is greater than that of `times_b`, it returns the string "times_b is faster". If both are equal, it returns the string "Both have the same average time".

You can assume that the input lists are non-empty.
user
Sure, here are the implementations of the two functions you asked for:

```python
def calculate_average_time(times: List[float]) -> float:
    return sum(times) / len(times)

def compare_execution_times(times_a: List[float], times_b: List[float]) -> str:
    avg_time_a = calculate_average_time(times_a)
    avg_time_b = calculate_average_time(times_b)

    if avg_time_a < avg_time_b:
        return "times_a is faster"
    elif avg_time_a > avg_time_b:
        return "times_b is faster"
    else:
        return "Both have the same average time"
```

In the first function, `calculate_average_time`, we calculate the average by summing all the elements in the list and dividing by the number of elements.

In the second function, `compare_execution_times`, we first calculate the average times of `times_a` and `times_b` using the `calculate_average_time` function. Then, we compare these averages to determine which one is faster, or if they are the same.
assistant