836. Rectangle Overlap

Solution idea

• 1-D: Two intervals (left1, right1) and (left2, right2) overlapped 的充分必要条件: left1 < right2 && left2 < right1

• 2-D: Two rectangles overlapped 的充分必要条件 就是 横坐标，纵坐标 分别满足上述条件

Time complexity = $O(1)$

Resource

1-line Solution, 1D to 2D