Count Odd XOR Pairs

Write a Python function `count_odd_xor_pairs(arr)` that takes a list of integers `arr` and returns the number of unique pairs `(i, j)` (where `i < j`) such that the XOR of the two numbers is odd.

#### Example Usage
```python [main.nopy]
print(count_odd_xor_pairs([5, 4, 7, 2, 1]))  # Output: 6
print(count_odd_xor_pairs([7, 2, 8, 1, 0, 5, 11]))  # Output: 12
print(count_odd_xor_pairs([1, 2, 3]))  # Output: 2
```

#### Constraints
- The input list will contain integers.
- The list may have up to 10,000 elements.
- The function should handle edge cases like empty lists or lists with one element.
def count_odd_xor_pairs(arr):
    """
    Count the number of unique pairs (i, j) such that the XOR of arr[i] and arr[j] is odd.

    Args:
    arr (list): A list of integers.

    Returns:
    int: The count of pairs with an odd XOR value.
    """
    # Placeholder for the solution
    pass
Intermediate loopsconditionals
More challenges to try
Calculate the exponential power of the given number Find Pair with Maximum Product Shell Sort Implementation Count Digits in String Sum Even Numbers at Even Positions Count Vowels in a String Sum of Fourth Power of Odd Numbers Find Max Length List Split List by Step Dog Age Calculator