Tristan's Collection of Interview Questions: Segment Tree and Interval Tree

Tristan's Collection of Interview Questions: Segment Tree and Interval Tree

To build a Segment Tree, first sort all the end points of the segments, than adding -infinity and +infinity. For n segments, we then partition (-infinity, +infinity) into 2n+1 segments. These 2n+1 segments serve as elementary intervals. From them (considering them as leafs),  we can build a balanced binary tree. Then we add the n segments into the tree. Each node represents an interval. Non-leaf nodes represent the interval which is the union of their children. When adding a segment, we store the information of that segment in all nodes where the nodes' intervals are within the segment's interval. Besides, the nodes' parents' interval are not within the segment's interval.

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