Principle
The calendar is stored as a binary tree where leafs represent elementary time periods. Other nodes represent the period of time covered by all their descendants.
The period of time covered by a reservation is represented by a set of "top-nodes". This set is the minimal set of nodes that exactly cover the reservation period of time.
A node of the binary tree is a "top-node" for a given reservation if
- all its descendants are inside the reservation period of time,
and
- it is the root node, or at least one descendant of the parent node is outside of the reservation period of time.
The following value is stored in each node:
q(node) = max(q(left child), q(right child)) + total amount of reserved resource for all reservations having this node as a "top-node"(for code optimization, the two parts of this sum are usually stored separately.)
Read more about this topic: Top-nodes Algorithm
Famous quotes containing the word principle:
“The only principle that does not inhibit progress is: anything goes.”
—Paul Feyerabend (1924–1994)
“The principle of majority rule is the mildest form in which the force of numbers can be exercised. It is a pacific substitute for civil war in which the opposing armies are counted and the victory is awarded to the larger before any blood is shed. Except in the sacred tests of democracy and in the incantations of the orators, we hardly take the trouble to pretend that the rule of the majority is not at bottom a rule of force.”
—Walter Lippmann (1889–1974)
“I often wish for the end of the wretched remnant of my life; and that wish is a rational one; but then the innate principle of self-preservation, wisely implanted in our natures, for obvious purposes, opposes that wish, and makes us endeavour to spin out our thread as long as we can, however decayed and rotten it may be.”
—Philip Dormer Stanhope, 4th Earl Chesterfield (1694–1773)