Find Missing and Repeated Values

lcpy gen -n 2965   # by problem number
lcpy gen -s find_missing_and_repeated_values   # by problem name

Input: grid = [[1,3],[2,2]]
Output: [2,4]
Explanation: Number 2 is repeated and number 4 is missing so the answer is [2,4].

Input: grid = [[9,1,7],[8,9,2],[3,4,6]]
Output: [9,5]
Explanation: Number 9 is repeated and number 5 is missing so the answer is [9,5].

class Solution:
    # Time: O(n^2)
    # Space: O(n^2)
    def find_missing_and_repeated_values(self, grid: list[list[int]]) -> list[int]:
        n = len(grid)
        counts: dict[int, int] = {}
        repeated = 0
        for row in grid:
            for val in row:
                if val in counts:
                    repeated = val
                counts[val] = counts.get(val, 0) + 1
        total = n * n
        missing = total * (total + 1) // 2 - sum(counts)
        return [repeated, missing]