Easy Python Solution
Code
# Code
```python3 []
class Solution:
    def miceAndCheese(self, reward1: List[int], reward2: List[int], k: int) -> int:
        n = len(reward1)
        hp = [(reward2[i] - reward1[i], reward1[i], reward2[i]) for i in range(n)]
        heapq.heapify(hp)
        res = 0
        for i in range(k):
            ele = heapq.heappop(hp)
            res += ele[1]
        while hp:
            ele = hp.pop()
            res += ele[2]
        return res
```
['Python3']