✅ One Line Solution
(Disclaimer: this is not an example to follow in a real project - it is written for fun and training mostly)Code #1Time complexity: O(n). Space complexity: O(1)
(Disclaimer: this is not an example to follow in a real project - it is written for fun and training mostly)

# Code #1
Time complexity: $$O(n)$$. Space complexity: $$O(1)$$.
```python3
class Solution:
    def canConstruct(self, s: str, k: int) -> bool:
        return sum(f&1 for f in Counter(s).values())<=k<=len(s)
```

# Code #2
Time complexity: $$O(n)$$. Space complexity: $$O(1)$$.
```python3
class Solution:
    def canConstruct(self, s: str, k: int) -> bool:
        return reduce(xor,(1<<ord(c)-97 for c in s)).bit_count()<=k<=len(s)
```

(Disclaimer 2: code above is just a product of fantasy packed into one line, it is not claimed to be 'true' oneliners - please, remind about drawbacks only if you know how to make it better)
['Hash Table', 'String', 'Counting', 'Python', 'Python3']