0 out of 464 challenges solved

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