At left subtree, [2,4] partially overlaps [0,2]. We'll check both directions.
- At left subtree, [2,4] does not overlap [0,1], so this is not going to contribute to our answer. We return infinity.
- At right subtree, [2,4] totally overlaps [2,2]. We return 4. The minimum of these two returned values(4, infinity) is 4. We get 4 from this portion.
At right subtree, [2,4] partially overlaps. So we'll check both directions.
- At left subtree, [2,4] completely overlaps [3,4]. We return 0.
- At right subtree, [2,4] doesn't overlap [5,5]. We return infinity. The minimum of these two returned values(0, infinity) is 0. We get 0 from this portion.

The minimum of the returned values(4,0) is 0. This is our desired minimum in range