How to use this applet

• Create new line segments by clicking and dragging in the drawing area on the left.
• You can also make random line segments by using the Generate button.
• Click on Start Building button on to finalize the segments and start building interval tree.

Building Mode

• In building mode, the median (dashed line) and segments stored on each tree node is displayed in the drawing area with the same color with the node.
• You can choose whether the lines are sorted by their left or right endpoints.
• Hover mouse on the nodes of the tree to see the corresponding median and segments in drawing area.
• Use Recurse button to recurse down the tree to either the left or right child node (depending on recursion status).
• Use Undo Recurse button to undo it.
• Use Finish Subtree button to finish the subtree on the current node and return to its parent.
• Click on Start Query button to proceed to the query mode.

Query Mode

• In query mode, only the segments intersecting the querying position are colored gradually as you run the algorithm.
• Drag the black vertical line on the drawing area to select a query position.
• The Recurse and Undo Recurse buttons have the same functionality; but the Finish Subtree button is not available since querying algorithm does not branch.