Brightest Position on Street Python Solution

lcpy gen -n 2021   # by problem number
lcpy gen -s brightest_position_on_street   # by problem name

Input: lights = [[-3,2],[1,2],[3,3]]
Output: -1
Explanation:
The first street lamp lights up the area from [(-3) - 2, (-3) + 2] = [-5, -1].
The second street lamp lights up the area from [1 - 2, 1 + 2] = [-1, 3].
The third street lamp lights up the area from [3 - 3, 3 + 3] = [0, 6].

Position -1 has a brightness of 2, illuminated by the first and second street light.
Positions 0, 1, 2, and 3 have a brightness of 2, illuminated by the second and third street light.
Out of all these positions, -1 is the smallest, so return it.

Input: lights = [[1,0],[0,1]]
Output: 1
Explanation:
The first street lamp lights up the area from [1 - 0, 1 + 0] = [1, 1].
The second street lamp lights up the area from [0 - 1, 0 + 1] = [-1, 1].

Position 1 has a brightness of 2, illuminated by the first and second street light.
Return 1 because it is the brightest position on the street.

Input: lights = [[1,2]]
Output: -1
Explanation:
The first street lamp lights up the area from [1 - 2, 1 + 2] = [-1, 3].

Positions -1, 0, 1, 2, and 3 have a brightness of 1, illuminated by the first street light.
Out of all these positions, -1 is the smallest, so return it.

class Solution:
    # Time: O(n log n)
    # Space: O(n)
    def brightest_position(self, lights: list[list[int]]) -> int:
        diff: dict[int, int] = {}
        for pos, rng in lights:
            diff[pos - rng] = diff.get(pos - rng, 0) + 1
            diff[pos + rng + 1] = diff.get(pos + rng + 1, 0) - 1

        best = 0
        brightness = 0
        best_pos = 0
        for point in sorted(diff):
            brightness += diff[point]
            if brightness > best:
                best = brightness
                best_pos = point
        return best_pos