disperazione 1

examples/edge_classify_2.py

@@ -46,6 +46,7 @@ class Graph:
     def add_edge(self, u, v):
         if u not in self.adjacency_list:
             self.adjacency_list[u] = []
+
         self.adjacency_list[u].append(v)
 
     def vertices(self):
@@ -56,10 +57,18 @@ class Graph:
 
 # Example usage:
 g = Graph()
+# g.add_edge(0, 1)
+# g.add_edge(1, 2)
+# g.add_edge(2, 3)
+# g.add_edge(3, 0)
+# g.add_edge(3, 4)
+# g.add_edge(4, 5)
+# g.add_edge(5, 0)
+# g.add_edge(4, 2)
+
 g.add_edge(0, 1)
 g.add_edge(1, 2)
-g.add_edge(2, 3)
-g.add_edge(3, 0)  # Creating the cycle 0 -> 1 -> 2 -> 3 -> 0
+g.add_edge(0, 2)
 
 # Running DFS
 results = dfs(g)

src/gfa/mod.rs

@@ -1,6 +1,6 @@
 use std::fmt::Display;
 
-#[derive(Debug, Hash, PartialEq, Eq, Clone)]
+#[derive(Debug, Hash, PartialEq, PartialOrd, Ord, Eq, Copy, Clone)]
 pub enum Orientation {
     Forward,
     Reverse,

src/graph/algorithms.rs

@@ -1,6 +1,6 @@
 use std::{
     cell::RefCell,
-    collections::{BTreeMap, HashMap, HashSet, VecDeque},
+    collections::{BTreeMap, BTreeSet, HashMap, HashSet, VecDeque},
     fmt::Debug,
     hash::Hash,
     rc::Rc,
@@ -13,41 +13,48 @@ use super::{AdjacencyGraph, UndirectedGraph};
 #[allow(dead_code)]
 impl<V> AdjacencyGraph<V>
 where
-    V: Hash + Eq + Clone + Debug,
+    V: Ord + Clone + Debug,
 {
     pub fn new() -> Self {
         AdjacencyGraph {
-            nodes: HashSet::new(),
-            adjacencies: HashMap::new(),
+            nodes: BTreeSet::new(),
+            adjacencies: BTreeMap::new(),
         }
     }
 
+    pub fn from_edges(edges: &[(V, V)]) -> Self {
+        let mut graph = AdjacencyGraph::new();
+
+        for (from, to) in edges {
+            graph.add_edge(from.clone(), to.clone());
+        }
+
+        graph
+    }
+
     pub fn add_node(&mut self, node: V) {
-        // O(1)
         self.nodes.insert(node);
     }
 
     pub fn add_edge(&mut self, from: V, to: V) {
-        // O(1)
         self.add_node(from.clone());
         self.add_node(to.clone());
 
-        // O(1)
         self.adjacencies
             .entry(from)
-            .or_insert_with(HashSet::new)
+            .or_insert_with(BTreeSet::new)
             .insert(to);
     }
 
-    pub fn get_adjacencies(&self, node: &V) -> Option<&HashSet<V>> {
+    pub fn get_adjacencies(&self, node: &V) -> Option<&BTreeSet<V>> {
         self.adjacencies.get(node)
     }
 
-    pub fn adjacencies(&self) -> &HashMap<V, HashSet<V>> {
+    pub fn adjacencies(&self) -> &BTreeMap<V, BTreeSet<V>> {
         &self.adjacencies
     }
 
-    pub fn nodes(&self) -> &HashSet<V> {
+    pub fn nodes(&self) -> &BTreeSet<V> {
         &self.nodes
     }
 
@@ -91,7 +98,7 @@ where
     }
 
     pub fn dfs<'a>(&'a self, node: &'a V) -> impl Iterator<Item = V> + 'a {
-        let mut visited = HashSet::new();
+        let mut visited = BTreeSet::new();
         let mut stack = VecDeque::from([node]);
 
         std::iter::from_fn(move || {
@@ -113,7 +120,7 @@ where
 
     /// This computes if this undirected graph is cyclic or not by searching for an oriented cycle in the graph
     pub fn is_cyclic(&self) -> bool {
-        let mut remaining_nodes = self.nodes.iter().collect::<HashSet<_>>();
+        let mut remaining_nodes = self.nodes.iter().collect::<BTreeSet<_>>();
 
         // let progress_bar = ProgressBar::new(self.nodes.len() as u64);
         // let mut visited_count = 0;
@@ -125,7 +132,7 @@ where
             remaining_nodes.remove(start);
             // progress_bar.inc(1);
 
-            let mut dfs_visited = HashSet::new();
+            let mut dfs_visited = BTreeSet::new();
             let mut stack = VecDeque::new();
             stack.push_back(start);
 
@@ -154,12 +161,12 @@ where
         false
     }
 
-    pub fn shortest_path_matrix(&self) -> HashMap<&V, HashMap<&V, usize>> {
-        let mut result = HashMap::new();
+    pub fn shortest_path_matrix(&self) -> BTreeMap<&V, BTreeMap<&V, usize>> {
+        let mut result = BTreeMap::new();
 
         for node in self.nodes.iter() {
-            let mut distances = HashMap::new();
-            let mut visited = HashSet::new();
+            let mut distances = BTreeMap::new();
+            let mut visited = BTreeSet::new();
             let mut queue = VecDeque::from([node]);
 
             distances.insert(node, 0);
@@ -190,7 +197,7 @@ where
     }
 
     pub fn compute_ccs(&self) -> Vec<Vec<V>> {
-        let mut visited = HashSet::new();
+        let mut visited = BTreeSet::new();
         let mut result = Vec::new();
 
         let op = self.opposite();
@@ -210,7 +217,7 @@ where
                 continue;
             }
 
-            let mut cc: HashSet<V> = HashSet::new();
+            let mut cc: BTreeSet<V> = BTreeSet::new();
             let mut stack: Vec<&V> = vec![node];
 
             while let Some(node) = stack.pop() {
@@ -240,82 +247,82 @@ where
         result
     }
 
-    pub fn compute_ccs_2(&self) -> Vec<Vec<V>> {
-        let mut cc: HashMap<V, Rc<RefCell<HashSet<V>>>> = HashMap::new();
+    // pub fn compute_ccs_2(&self) -> Vec<Vec<V>> {
+    //     let mut cc: BTreeMap<V, Rc<RefCell<BTreeSet<V>>>> = BTreeMap::new();
 
-        for node in self.nodes.iter() {
-            if cc.contains_key(&node) {
-                continue;
-            }
+    //     for node in self.nodes.iter() {
+    //         if cc.contains_key(&node) {
+    //             continue;
+    //         }
 
-            // println!("All CC: {:?}", cc);
+    //         // println!("All CC: {:?}", cc);
 
-            let new_cc = Rc::new(RefCell::new(HashSet::new()));
+    //         let new_cc = Rc::new(RefCell::new(HashSet::new()));
 
-            let mut stack: Vec<&V> = vec![node];
+    //         let mut stack: Vec<&V> = vec![node];
 
-            while let Some(node) = stack.pop() {
-                // println!("New CC: {:?}", new_cc.borrow());
+    //         while let Some(node) = stack.pop() {
+    //             // println!("New CC: {:?}", new_cc.borrow());
 
-                if cc.contains_key(&node) {
-                    // merge the two connected components and go to the next node
+    //             if cc.contains_key(&node) {
+    //                 // merge the two connected components and go to the next node
 
-                    let old_cc: &Rc<RefCell<HashSet<V>>> = cc.get(&node).unwrap();
+    //                 let old_cc: &Rc<RefCell<HashSet<V>>> = cc.get(&node).unwrap();
 
-                    // println!(
-                    //     "Merging {:?} with {:?} due to link to {:?}",
-                    //     new_cc.borrow(),
-                    //     old_cc.borrow(),
-                    //     node
-                    // );
+    //                 // println!(
+    //                 //     "Merging {:?} with {:?} due to link to {:?}",
+    //                 //     new_cc.borrow(),
+    //                 //     old_cc.borrow(),
+    //                 //     node
+    //                 // );
 
-                    new_cc
-                        .borrow_mut()
-                        .extend(old_cc.borrow().iter().map(|x| x.to_owned()));
+    //                 new_cc
+    //                     .borrow_mut()
+    //                     .extend(old_cc.borrow().iter().map(|x| x.to_owned()));
 
-                    break;
-                }
+    //                 break;
+    //             }
 
-                if new_cc.borrow().contains(&node) {
-                    continue;
-                }
+    //             if new_cc.borrow().contains(&node) {
+    //                 continue;
+    //             }
 
-                new_cc.borrow_mut().insert(node.clone());
+    //             new_cc.borrow_mut().insert(node.clone());
 
-                if let Some(adjacencies) = self.get_adjacencies(&node) {
-                    for adj in adjacencies {
-                        stack.push(adj);
-                    }
-                }
-            }
+    //             if let Some(adjacencies) = self.get_adjacencies(&node) {
+    //                 for adj in adjacencies {
+    //                     stack.push(adj);
+    //                 }
+    //             }
+    //         }
 
-            for n in new_cc.borrow().iter() {
-                cc.insert(n.to_owned(), new_cc.clone());
-            }
-        }
+    //         for n in new_cc.borrow().iter() {
+    //             cc.insert(n.to_owned(), new_cc.clone());
+    //         }
+    //     }
 
-        // extract the unique connected components by pointers
-        let mut result = Vec::new();
-        let mut seen = HashSet::new();
+    //     // extract the unique connected components by pointers
+    //     let mut result = Vec::new();
+    //     let mut seen = HashSet::new();
 
-        for node in self.nodes.iter() {
-            if seen.contains(node) {
-                continue;
-            }
+    //     for node in self.nodes.iter() {
+    //         if seen.contains(node) {
+    //             continue;
+    //         }
 
-            let cc = cc.get(node).unwrap();
-            seen.extend(cc.borrow().iter().map(|x| x.to_owned()));
+    //         let cc = cc.get(node).unwrap();
+    //         seen.extend(cc.borrow().iter().map(|x| x.to_owned()));
 
-            result.push(cc.borrow().iter().map(|x| x.to_owned()).collect());
-        }
+    //         result.push(cc.borrow().iter().map(|x| x.to_owned()).collect());
+    //     }
 
-        result
-    }
+    //     result
+    // }
 
     /// This function prints the number of nodes, edges and a histogram of the degrees of the nodes
     /// in the graph (computing the degrees might take a long time)
     pub fn print_stats(&self) {
-        let mut vertices_degrees = HashMap::new();
+        let mut vertices_degrees = BTreeMap::new();
 
         for (from, tos) in self
             .adjacencies
@@ -356,10 +363,10 @@ where
 
 impl<V> UndirectedGraph<V>
 where
-    V: Hash + Eq + Clone + Debug,
+    V: Ord + Eq + Clone + Debug,
 {
     pub fn connected_components(&self) -> Vec<Vec<V>> {
-        let mut visited = HashSet::new();
+        let mut visited = BTreeSet::new();
         let mut result = Vec::new();
 
         for node in self.graph.nodes.iter() {
@@ -367,7 +374,7 @@ where
                 continue;
             }
 
-            let mut cc: HashSet<V> = HashSet::new();
+            let mut cc: BTreeSet<V> = BTreeSet::new();
             let mut stack: Vec<&V> = vec![node];
 
             while let Some(node) = stack.pop() {

src/graph/edge_types.rs

@@ -1,6 +1,6 @@
 use std::{
     cmp::Ordering,
-    collections::{HashMap, HashSet},
+    collections::{BTreeMap, BTreeSet, HashMap, HashSet},
     fmt::Debug,
     hash::Hash,
 };
@@ -17,106 +17,202 @@ pub enum EdgeType {
     CrossEdge,
 }
 
-impl<V> AdjacencyGraph<V>
+struct ClassifyState<V> {
+    progress_bar: ProgressBar,
+
+    edge_types: BTreeMap<(V, V), EdgeType>,
+
+    visited: BTreeSet<V>,
+
+    start_times: BTreeMap<V, i32>,
+    finished_nodes: BTreeSet<V>,
+
+    time: i32,
+}
+
+impl<V> ClassifyState<V>
 where
-    V: Hash + Eq + Clone + Debug,
+    V: Ord + Eq + Clone + Debug,
 {
-    pub fn compute_edge_types(&self) -> HashMap<(&V, &V), EdgeType> {
-        let mut edge_types = HashMap::new();
+    pub fn classify_edges_rec(mut self, graph: &AdjacencyGraph<V>) -> BTreeMap<(V, V), EdgeType> {
+        for start in graph.nodes().iter() {
+            if self.visited.contains(start) {
+                continue;
+            }
 
-        // TODO: ...
+            self.dfs(graph, start, None);
+        }
 
-        return edge_types;
+        self.progress_bar.finish();
+        return self.edge_types;
     }
 
-    // pub fn compute_edge_types(&self) -> HashMap<(&V, &V), EdgeType> {
-    //     /// To correctly compute the start and end times of the nodes in the
-    //     /// graph, we need to keep do work before and after the recursion call
-    //     enum RecurseState<'a, V> {
-    //         Before(&'a V),
-    //         BeforeNeighbor(&'a V, &'a V),
-    //         AfterNeighbor(&'a V),
-    //     }
+    pub fn dfs(&mut self, graph: &AdjacencyGraph<V>, node: &V, parent: Option<&V>) {
+        if self.visited.contains(node) {
+            return;
+        }
+
+        self.progress_bar.inc(1);
+        self.visited.insert(node.clone());
+        self.time += 1;
+        self.start_times.insert(node.clone(), self.time);
+
+        if let Some(parent) = parent {
+            self.edge_types
+                .insert((parent.clone(), node.clone()), EdgeType::TreeEdge);
+        }
+
+        if let Some(adjacencies) = graph.get_adjacencies(node) {
+            for adj in adjacencies.iter() {
+                if !self.visited.contains(adj) {
+                    self.dfs(graph, adj, Some(node));
+                } else {
+                    if !self.finished_nodes.contains(adj) {
+                        self.edge_types
+                            .insert((node.clone(), adj.clone()), EdgeType::BackEdge);
+                    } else if self.start_times.get(node) < self.start_times.get(adj) {
+                        self.edge_types
+                            .insert((node.clone(), adj.clone()), EdgeType::ForwardEdge);
+                    } else {
+                        self.edge_types
+                            .insert((node.clone(), adj.clone()), EdgeType::CrossEdge);
+                    }
+                }
+            }
+        }
+
+        self.time += 1;
+        self.finished_nodes.insert(node.clone());
+    }
+}
+
+impl<V> AdjacencyGraph<V>
+where
+    V: Ord + Eq + Clone + Debug,
+{
+    pub fn compute_edge_types_rec(&self) -> BTreeMap<(V, V), EdgeType> {
+        return ClassifyState {
+            progress_bar: ProgressBar::new(self.nodes().len() as u64),
+
+            edge_types: BTreeMap::new(),
+            visited: BTreeSet::new(),
+            start_times: BTreeMap::new(),
+            finished_nodes: BTreeSet::new(),
+            time: 0,
+        }
+        .classify_edges_rec(self);
+    }
+
+    // pub fn compute_edge_types(&self) -> BTreeMap<(V, V), EdgeType> {
+    //     println!("{:?}", self);
+
+    //     let mut edge_types: BTreeMap<(V, V), EdgeType> = BTreeMap::new();
+    //     let mut visited: BTreeSet<V> = BTreeSet::new();
 
-    //     let mut edge_types = HashMap::new();
+    //     let mut start_times: BTreeMap<V, i32> = BTreeMap::new();
+    //     let mut finished_nodes: BTreeSet<V> = BTreeSet::new();
 
-    //     let mut visited = HashSet::new();
-    //     let mut start_times = HashMap::new();
-    //     let mut finished_nodes = HashSet::new();
+    //     #[derive(Debug)]
+    //     enum RecurseState<V> {
+    //         Visit { node: V, parent: Option<V> },
+    //         End { node: V },
+    //     }
 
     //     let mut time = 0;
 
-    //     let progress_bar = ProgressBar::new(self.nodes().len() as u64);
+    //     // let progress_bar = ProgressBar::new(self.nodes().len() as u64);
 
-    //     for node in self.nodes().iter() {
-    //         if visited.contains(node) {
+    //     for start in self.nodes().iter() {
+    //         if visited.contains(start) {
     //             continue;
     //         }
 
-    //         let mut stack = Vec::new();
-
-    //         stack.push(RecurseState::Before(node));
+    //         let mut stack: Vec<RecurseState<V>> = Vec::new();
 
-    //         while let Some(state) = stack.pop() {
-    //             match state {
-    //                 RecurseState::Before(node) => {
-    //                     progress_bar.inc(1);
-    //                     visited.insert(node.clone());
-    //                     start_times.insert(node, time);
-    //                     time += 1;
+    //         // The first node does not have a parent
+    //         stack.push(RecurseState::End {
+    //             node: start.clone(),
+    //         });
+    //         stack.push(RecurseState::Visit {
+    //             node: start.clone(),
+    //             parent: None,
+    //         });
 
-    //                     // it is extremely important that this before the adjacencies to correctly
-    //                     // iterate over the graph
+    //         println!("Starting DFS from {:?}", start);
 
-    //                     if let Some(adjacencies) = self.get_adjacencies(node) {
-    //                         for adj in adjacencies {
-    //                             println!("Node: {:?} Adj: {:?}", node, adj,);
+    //         while let Some(state) = stack.pop() {
+    //             println!("Current: {:?}", state);
+    //             println!("Finished Nodes: {:?}", finished_nodes);
 
-    //                             stack.push(RecurseState::AfterNeighbor(node));
+    //             match state {
+    //                 RecurseState::Visit { node, parent } => {
+    //                     if visited.contains(&node) {
+    //                         // progress_bar.inc(1);
+    //                     }
 
-    //                             if !visited.contains(adj) {
-    //                                 edge_types.insert((node, adj), EdgeType::TreeEdge);
-    //                                 stack.push(RecurseState::Before(adj));
+    //                     if let Some(parent) = parent.clone() {
+    //                         if !visited.contains(&node) {
+    //                             println!("{:?} => TreeEdge", (parent.clone(), node.clone()));
+    //                             edge_types
+    //                                 .insert((parent.clone(), node.clone()), EdgeType::TreeEdge);
     //                         } else {
-    //                                 stack.push(RecurseState::BeforeNeighbor(node, adj));
-    //                             }
+    //                             if !finished_nodes.contains(&parent) {
+    //                                 println!("{:?} => BackEdge", (parent.clone(), node.clone()));
+    //                                 edge_types
+    //                                     .insert((node.clone(), parent.clone()), EdgeType::BackEdge);
+    //                             } else if start_times.get(&node) < start_times.get(&parent) {
+    //                                 println!("{:?} => ForwardEdge", (parent.clone(), node.clone()));
+    //                                 edge_types.insert(
+    //                                     (node.clone(), parent.clone()),
+    //                                     EdgeType::ForwardEdge,
+    //                                 );
+    //                             } else {
+    //                                 println!("{:?} => CrossEdge", (parent.clone(), node.clone()));
+    //                                 edge_types.insert(
+    //                                     (node.clone(), parent.clone()),
+    //                                     EdgeType::CrossEdge,
+    //                                 );
     //                             }
     //                         }
     //                     }
-    //                 RecurseState::AfterNeighbor(node) => {
-    //                     finished_nodes.insert(node);
+
     //                     time += 1;
-    //                 }
-    //                 RecurseState::BeforeNeighbor(node, adj) => {
-    //                     let start_time_node = start_times.get(node).unwrap();
-    //                     let start_time_adj = start_times.get(adj).unwrap();
-    //                     let end_time_node = finished_nodes.get(node).unwrap_or(&0);
-    //                     let end_time_adj = finished_nodes.get(adj).unwrap_or(&0);
-
-    //                     println!(
-    //                         "Times: ({:?}, {:?}) ({:?}, {:?})",
-    //                         start_time_node, end_time_node, start_time_adj, end_time_adj
-    //                     );
+    //                     start_times.insert(node.clone(), time);
+
+    //                     visited.insert(node.clone());
 
-    //                     match (
-    //                         start_time_node.cmp(start_time_adj),
-    //                         end_time_node.cmp(end_time_adj),
-    //                     ) {
-    //                         (Ordering::Less, Ordering::Greater) => {
-    //                             edge_types.insert((node, adj), EdgeType::ForwardEdge);
+    //                     // it is extremely important that this before the adjacencies to correctly
+    //                     // iterate over the graph
+    //                     // stack.push(RecurseState::AfterNeighbors { node });
+
+    //                     if let Some(adjacencies) = self.get_adjacencies(&node) {
+    //                         println!("adjacencies: {:?}", adjacencies);
+    //                         for adj in adjacencies.iter().rev() {
+    //                             if !visited.contains(&adj) {
+    //                                 stack.push(RecurseState::End { node: adj.clone() });
+    //                                 stack.push(RecurseState::Visit {
+    //                                     node: adj.clone(),
+    //                                     parent: Some(node.clone()),
+    //                                 });
     //                             }
-    //                         (Ordering::Greater, Ordering::Less) => {
-    //                             edge_types.insert((node, adj), EdgeType::BackEdge);
     //                         }
-    //                         _ => {
-    //                             edge_types.insert((node, adj), EdgeType::CrossEdge);
     //                     }
     //                 }
+    //                 RecurseState::End { node } => {
+    //                     time += 1;
+    //                     finished_nodes.insert(node.clone());
     //                 }
     //             }
+
+    //             println!();
+
+    //             // println!("after:");
+    //             // println!("~> {:?}", stack);
     //         }
     //     }
 
-    //     edge_types
+    //     // progress_bar.finish();
+
+    //     return edge_types;
     // }
 }

src/graph/mod.rs

@@ -1,5 +1,5 @@
 use std::{
-    collections::{HashMap, HashSet},
+    collections::{BTreeMap, BTreeSet, HashSet},
     fmt::Debug,
     hash::Hash,
 };
@@ -7,15 +7,15 @@ use std::{
 #[derive(Debug)]
 pub struct AdjacencyGraph<V>
 where
-    V: Hash + Eq + Clone,
+    V: Clone,
 {
-    nodes: HashSet<V>,
-    adjacencies: HashMap<V, HashSet<V>>,
+    nodes: BTreeSet<V>,
+    adjacencies: BTreeMap<V, BTreeSet<V>>,
 }
 
 pub struct UndirectedGraph<V>
 where
-    V: Hash + Eq + Clone,
+    V: Clone,
 {
     graph: AdjacencyGraph<V>,
 }
@@ -29,29 +29,97 @@ mod tests {
 
     use super::*;
 
+    fn print_edge_types<T>(edge_types: &BTreeMap<(T, T), edge_types::EdgeType>)
+    where
+        T: Debug,
+    {
+        println!("");
+        println!("Edge types:");
+
+        for (edge, edge_type) in edge_types {
+            println!("{:?} -> {:?}: {:?}", edge.0, edge.1, edge_type);
+        }
+
+        // for (edge_type, edges) in edge_types
+        //     .iter()
+        //     .fold(BTreeMap::new(), |mut acc, (edge, edge_type)| {
+        //         acc.entry(edge_type).or_insert_with(Vec::new).push(edge);
+        //         acc
+        //     })
+        //     .iter()
+        // {
+        //     println!("- {:?}", edge_type);
+        //     for edge in edges {
+        //         println!("{:?}", edge);
+        //     }
+        // }
+    }
+
+    #[test]
+    fn test_compute_edge_types_cycle() {
+        let g = AdjacencyGraph::from_edges(&[(0, 1), (1, 2), (2, 3), (3, 0)]);
+
+        let edge_types = g.compute_edge_types_rec();
+        print_edge_types(&edge_types);
+
+        assert_eq!(edge_types.len(), 4);
+        assert_eq!(edge_types[&(0, 1)], edge_types::EdgeType::TreeEdge);
+        assert_eq!(edge_types[&(1, 2)], edge_types::EdgeType::TreeEdge);
+        assert_eq!(edge_types[&(2, 3)], edge_types::EdgeType::TreeEdge);
+        assert_eq!(edge_types[&(3, 0)], edge_types::EdgeType::BackEdge);
+    }
+
     #[test]
-    fn test_compute_edge_types() {
-        let mut g = AdjacencyGraph::new();
-
-        g.add_edge(1, 2);
-        g.add_edge(2, 3);
-        g.add_edge(3, 4);
-        g.add_edge(4, 1);
-
-        let edge_types = g.compute_edge_types();
-        let edge_type_dict =
-            edge_types
-                .iter()
-                .fold(BTreeMap::new(), |mut acc, (edge, edge_type)| {
-                    acc.entry(edge_type).or_insert_with(Vec::new).push(edge);
-                    acc
-                });
-
-        for (edge_type, edges) in edge_type_dict.iter() {
-            println!("- {:?}", edge_type);
-            for edge in edges {
-                println!("Edge: {:?}", edge);
+    fn test_compute_edge_types_forward() {
+        let g = AdjacencyGraph::from_edges(&[(0, 1), (1, 2), (0, 2)]);
+
+        let edge_types = g.compute_edge_types_rec();
+        print_edge_types(&edge_types);
+
+        assert_eq!(edge_types.len(), 3);
+        assert_eq!(edge_types[&(0, 1)], edge_types::EdgeType::TreeEdge);
+        assert_eq!(edge_types[&(1, 2)], edge_types::EdgeType::TreeEdge);
+        assert_eq!(edge_types[&(0, 2)], edge_types::EdgeType::ForwardEdge);
     }
+
+    #[test]
+    fn test_compute_edge_types_cross() {
+        let g = AdjacencyGraph::from_edges(&[(0, 1), (1, 2), (0, 3), (3, 4), (2, 4)]);
+
+        let edge_types = g.compute_edge_types_rec();
+        print_edge_types(&edge_types);
+
+        assert_eq!(edge_types.len(), 5);
+        assert_eq!(edge_types[&(0, 1)], edge_types::EdgeType::TreeEdge);
+        assert_eq!(edge_types[&(1, 2)], edge_types::EdgeType::TreeEdge);
+        assert_eq!(edge_types[&(0, 3)], edge_types::EdgeType::TreeEdge);
+        assert_eq!(edge_types[&(2, 4)], edge_types::EdgeType::TreeEdge);
+        assert_eq!(edge_types[&(3, 4)], edge_types::EdgeType::CrossEdge);
     }
+
+    #[test]
+    fn test_compute_edge_types_all() {
+        let g = AdjacencyGraph::from_edges(&[
+            //
+            ("u", "v"),
+            ("u", "x"),
+            ("v", "y"),
+            ("y", "x"),
+            ("x", "v"),
+            ("w", "y"),
+            ("w", "z"),
+        ]);
+
+        let edge_types = g.compute_edge_types_rec();
+        print_edge_types(&edge_types);
+
+        assert_eq!(edge_types.len(), 7);
+        assert_eq!(edge_types[&("u", "v")], edge_types::EdgeType::TreeEdge);
+        assert_eq!(edge_types[&("u", "x")], edge_types::EdgeType::ForwardEdge);
+        assert_eq!(edge_types[&("v", "y")], edge_types::EdgeType::TreeEdge);
+        assert_eq!(edge_types[&("y", "x")], edge_types::EdgeType::TreeEdge);
+        assert_eq!(edge_types[&("x", "v")], edge_types::EdgeType::BackEdge);
+        assert_eq!(edge_types[&("w", "y")], edge_types::EdgeType::CrossEdge);
+        assert_eq!(edge_types[&("w", "z")], edge_types::EdgeType::TreeEdge);
     }
 }

src/main.rs

@@ -94,7 +94,7 @@ fn main() -> std::io::Result<()> {
 
             // println!("Graph has cycles: {}", graph.is_cyclic());
 
-            let edge_types = graph.compute_edge_types();
+            let edge_types = graph.compute_edge_types_rec();
 
             let edge_type_histogram: BTreeMap<_, _> = edge_types
                 .iter()