Intervals - Miscellaneous / Interval

The usage of “x” and “y” in the diagram above makes this content difficult to understand, since on a cartesian plane variables named “x1” and “y1” would typically be paired together.

Given that the algorithm for solving these involves sorting these, using “left” and “right” may make this clearer.
This would make the answer to query #1: “max(left1, right1) <= min(left2, right2)”.
Or using “a” and “b”: “max(a1, b1) <= min(a2, b2)”.