Segment Tree of Placements

The pstree crate allows you to create an n to k segment tree of placements based on a key in the range 0..=n. This key will be used as the root and leaves of the tree. So other vertices will be taken in the ranges 0..key and key + 1..=n.

The structure is designed to quickly respond to queries to change a vertex or edge in a weighted directed graph that allows edges of negative weight.

Example

```rust use pstree::PSTree;

fn main() { let pstree = PSTree::new(3, 2, 0, 0); let shortest = pstree.updatevertex(1, 1); let shortest = pstree.updateedge(0, 1, 2); } ```

The PSTree::new(3, 2, 0, 0) creates a 3 by 2 tree of placements based on key 0 with initial value 0:

0 ├── 1 │ ├── 2 │ │ └── 0 │ └── 3 │ └── 0 ├── 2 │ ├── 1 │ │ └── 0 │ └── 3 │ └── 0 └── 3 ├── 1 │ └── 0 └── 2 └── 0

The pstree.update_vertex(1, 1) updates vertex 1 with value 1, so the distances will be recalculated, returning the shortest distance from key of length k:

0 ├── 1 │ '-- 2 │ ' '-- 0 │ '-- 3 │ '-- 0 ├── 2 │ ├── 1 │ │ '-- 0 │ └── 3 │ └── 0 └── 3 ├── 1 │ '-- 0 └── 2 └── 0

The pstree.update_edge(0, 1, 2) updates edge from 0 to 1 with value 2, so the distances will be recalculated, returning the shortest distance from key of length k:

0 '-- 1 │ '-- 2 │ ' '-- 0 │ '-- 3 │ '-- 0 ├── 2 │ ├── 1 │ │ └── 0 │ └── 3 │ └── 0 └── 3 ├── 1 │ └── 0 └── 2 └── 0

Usage

[dependencies] pstree = "0.1"

License

Licensed under either of

at your option.