题目：
题解：
class Solution:def __init__(self, rects: List[List[int]]):self.rects = rectsself.sum = [0]for a, b, x, y in rects:self.sum.append(self.sum[-1] + (x - a + 1) * (y - b + 1))def pick(self) -> List[int]:k = randrange(self.sum[-1])rectIndex = bisect_right(self.sum, k) - 1a, b, _, y = self.rects[rectIndex]da, db = divmod(k - self.sum[rectIndex], y - b + 1)return [a + da, b + db]
