Benchmarks

Cargo.toml

@@ -3,14 +3,16 @@ name = "lctree"
 version = "0.1.2"
 edition = "2021"
 rust-version = "1.63"
+description = "Rust implementation of Link-Cut-Tree: self-balancing data structure to maintain a forest of rooted trees."
 readme = "README.md"
+documentation = "https://docs.rs/lctree"
+homepage = "https://github.com/azizkayumov/lctree"
+repository = "https://github.com/azizkayumov/lctree"
 license = "Apache-2.0"
 keywords = ["tree", "dynamic-connectivity"]
 categories = ["algorithms", "data-structures"]
 authors = ["Kayumov A.I. <[email protected]>"]
 exclude = ["./github"]
-description = "Rust implementation of Link-Cut-Tree: self-balancing data structure to maintain a forest of rooted trees."
-repository = "https://github.com/azizkayumov/lctree"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 

README.md

@@ -2,15 +2,15 @@
 [![crates.io](https://img.shields.io/crates/v/lctree)](https://crates.io/crates/lctree)
 
 # lctree
-Rust implementation of [Link-Cut-Tree](https://dl.acm.org/doi/10.1145/253262.253347](https://dl.acm.org/doi/pdf/10.1145/800076.802464)): self-balancing data structure to maintain a forest of rooted trees through linking and cutting edges.
+Rust implementation of [Link-Cut-Tree](https://dl.acm.org/doi/10.1145/253262.253347](https://dl.acm.org/doi/pdf/10.1145/800076.802464)): self-balancing data structure to maintain a forest of rooted trees through dynamically linking and cutting edges.
 
 ## Example
 This example shows how to link and cut edges:
 ```rust
 use lctree::LinkCutTree;
 
 fn main() {
-    // We form a link-cut tree from a rooted tree with the following structure:
+    // We form a link-cut tree from the following rooted tree:
     //     0
     //    / \
     //   1   4

src/lib.rs

@@ -92,6 +92,10 @@ impl LinkCutTree {
         }
         // detach w from its parent (which is v)
         if let Some(left) = self.forest[w].left {
+            if left != v {
+                eprintln!("Error: no link between {v} and {w}"); // maybe this should be a panic?
+                return;
+            }
             self.forest[w].left = None;
             self.forest[left].parent = Parent::Root;
         }
@@ -236,7 +240,7 @@ mod tests {
 
     #[test]
     pub fn cut() {
-        // We form a link-cut tree from a rooted tree with the following structure:
+        // We form a link-cut tree from the following rooted tree:
         //     0
         //    / \
         //   1   6
@@ -299,9 +303,32 @@ mod tests {
         }
     }
 
+    #[test]
+    pub fn cut_non_existing_edge() {
+        // We form a link-cut tree from the following rooted tree:
+        //     0
+        //    / \
+        //   1   2
+        //       |
+        //       3
+        let mut lctree = super::LinkCutTree::new();
+        for i in 0..4 {
+            lctree.make_tree(i as f64);
+        }
+        lctree.link(1, 0);
+        lctree.link(2, 0);
+        lctree.link(3, 2);
+
+        // Try to cut non-existing edge:
+        lctree.cut(1, 3); // should do nothing
+
+        // They should still be connected:
+        assert!(lctree.connected(1, 3));
+    }
+
     #[test]
     pub fn findroot() {
-        // We form a link-cut tree from a rooted tree with the following structure:
+        // We form a link-cut tree from the following rooted tree:
         //     0
         //    / \
         //   1   6
@@ -356,7 +383,7 @@ mod tests {
 
     #[test]
     pub fn reroot() {
-        // We form a link-cut tree from a rooted tree with the following structure:
+        // We form a link-cut tree from the following rooted tree:
         //     0
         //    / \
         //   1   4
@@ -392,7 +419,7 @@ mod tests {
             lctree.make_tree(weights[i]);
         }
 
-        // We form a link-cut tree from a rooted tree with the following structure
+        // We form a link-cut tree from the following rooted tree
         // (the numbers in parentheses are the weights of the nodes):
         //           0(9)
         //           /  \

tests/README.md

@@ -0,0 +1,11 @@
+### Benchmark
+This benchmark report contains overall running time analysis of Link-Cut trees in comparison to its brute-force counterpart.
+Each test performs a number of random operations (`link(v, w)`, `cut(v, w)`, `connected(v, w)` or `findmax(v, w)`) on forests of varying sizes.
+
+| # Nodes     | # Operations    | Random seed           | [lctree](https://github.com/azizkayumov/lctree/blob/main/src/lib.rs)    | [brute-force](https://github.com/azizkayumov/lctree/blob/main/tests/test_random.rs)  | 
+| :---        | :---            | :---                  | :---          | :---          |
+| 100         | 10K             | 564315935137013477    | 6.567967ms    | 53.48109ms    |
+| 100         | 100K            | 5233351911053448040   | 44.379304ms   | 321.900746ms  |
+| 100         | 1M              | 10905789823848117209  | 476.117191ms  | 3.915883695s  |
+| 500         | 2M              | 5863263585868731364   | 984.139022ms  | 11.542679321s |
+| 1000        | 5M              | 11338885474432604336  | 2.371485318s  | 23.710666403s |