still broken !

This commit is contained in:
jacekpoz 2024-06-22 18:23:04 +02:00
parent 9c9b46d31d
commit 6f1a45c954
Signed by: poz
SSH key fingerprint: SHA256:JyLeVWE4bF3tDnFeUpUaJsPsNlJyBldDGV/dIKSLyN8

View file

@ -42,18 +42,23 @@ impl Ord for Edge {
pub struct Graph {
pub size: usize,
pub edges: Vec<Edge>,
pub edges: Vec<Vec<f64>>,
}
impl Graph {
pub fn new(size: usize) -> Self {
Self {
size,
edges: (0..size).map(|u|
(0..size).map(|v|
Edge { src: u, dst: v, weight: 0.0 }
).collect::<Vec<_>>()
).flatten()
// edges: (0..size).map(|u|
// (0..size).map(|v|
// Edge { src: u, dst: v, weight: 0.0 }
// ).collect::<Vec<_>>()
// ).flatten()
// .collect::<Vec<_>>(),
edges: (0..size)
.map(|_| (0..size)
.map(|_| 0.0)
.collect::<Vec<_>>())
.collect::<Vec<_>>(),
}
}
@ -63,112 +68,71 @@ impl Graph {
size,
edges: (0..size).map(|u|
(0..size).map(|v|
Edge {
src: u,
dst: v,
weight: if u == v { 0.0 }
if u == v { 0.0 }
else { thread_rng().gen::<f64>() }
}
).collect::<Vec<_>>()
).flatten()
).collect::<Vec<_>>())
.collect::<Vec<_>>(),
}
}
pub fn vertex(&self, u: usize, v: usize) -> Option<f64> {
if u >= self.size || v >= self.size {
return None;
}
Some(self.edges.iter().find(|e| e.src == u && e.dst == v).unwrap().weight)
pub fn edges(&self) -> Vec<Edge> {
(0..self.size)
.map(|i|
(0..self.size)
.map(|j| Edge {
src: i,
dst: j,
weight: self.edges[i][j],
})
.collect::<Vec<_>>()
)
.flatten()
.collect::<Vec<_>>()
}
pub fn prim(&self) -> Vec<Edge> {
// Associate with each vertex v of the graph a number C[v] (the cheapest cost of a connection to v) and an edge E[v] (the edge providing that cheapest connection). To initialize these values, set all values of C[v] to +∞ (or to any number larger than the maximum edge weight) and set each E[v] to a special flag value indicating that there is no edge connecting v to earlier vertices.
let mut min_edges = (0..self.size)
.map(|i|
*self.edges.iter()
.filter(|e| (e.src == i || e.dst == i) && e.src != e.dst)
.min()
.unwrap()
).collect::<Vec<_>>();
// dbg!(&min_edges);
let mut parent = vec![0; self.size];
// helper struct for the queue
#[derive(Clone, Debug)]
struct Vertex {
index: usize,
min_weight: f64,
}
let mut key = vec![f64::INFINITY; self.size];
impl Hash for Vertex {
fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
self.index.hash(state);
let mut mst_set = vec![false; self.size];
key[0] = 0.0;
parent[0] = usize::MAX;
for _ in 0..(self.size - 1) {
let u = {
let mut min_index = 0;
let mut min = f64::MAX;
for k in 0..self.size {
if mst_set[k] == false && key[k] < min {
min = key[k];
min_index = k;
}
}
impl PartialEq for Vertex {
fn eq(&self, other: &Self) -> bool {
self.min_weight == other.min_weight
}
}
min_index
};
impl Eq for Vertex {}
mst_set[u] = true;
impl PartialOrd for Vertex {
fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
self.min_weight.partial_cmp(&other.min_weight)
}
}
impl Ord for Vertex {
fn cmp(&self, other: &Self) -> Ordering {
self.min_weight.total_cmp(&other.min_weight)
}
}
// Initialize an empty forest F
let mut forest = vec![];
// and a set Q of vertices
let mut queue = BinaryHeap::<Reverse<Vertex>>::new();
// that have not yet been included in F (initially, all vertices).
(0..self.size)
.map(|i| Vertex { index: i, min_weight: min_edges[i].weight })
.for_each(|v| queue.push(Reverse(v)));
// Repeat the following steps until Q is empty:
// Find and remove a vertex v from Q having the minimum possible value of C[v]
while let Some(Reverse(v)) = queue.pop() {
// Add v to F
forest.push(v.clone());
// Loop over the edges vw connecting v to other vertices w.
for vw in self.edges.iter()
.filter(|e| (e.src == v.index || e.dst == v.index) && e.src != e.dst) {
// the vertex in the current edge that isn't v.src
let w = if vw.src == v.index { vw.dst } else { vw.src };
// For each such edge, if w still belongs to Q and vw has smaller weight than C[w], perform the following steps:
if queue.clone().iter().any(|Reverse(e)| e.index == w || e.index == w) && vw.weight < min_edges[w].weight {
dbg!(&w);
// Set C[w] to the cost of edge vw
// Set E[w] to point to edge vw.
min_edges[w] = *vw;
for v in 0..self.size {
let w = self.edges[u][v];
if u != v && mst_set[v] == false && w < key[v] {
parent[v] = u;
key[v] = w;
}
}
}
// dbg!(&min_edges);
// Return F, which specifically includes the corresponding edges in E
forest.iter()
.map(|i| min_edges[i.index])
// deduplication
.collect::<HashSet<_>>()
.iter()
.map(|e| *e)
.collect::<Vec<_>>()
(1..self.size)
.map(|i| Edge {
src: parent[i],
dst: i,
weight: self.edges[i][parent[i]],
})
.collect()
}
fn find_id(belongs: &mut Vec<usize>, i: usize) -> usize {
@ -194,7 +158,8 @@ impl Graph {
}
pub fn kruskal(&self) -> Vec<Edge> {
let mut edges = self.edges.iter()
let edges = self.edges();
let mut edges = edges.iter()
.filter(|e| e.weight != 0.0)
.collect::<Vec<_>>();
@ -224,7 +189,7 @@ impl Display for Graph {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
for i in 0..self.size {
for j in 0..self.size {
write!(f, "{weight:.6} ", weight = self.vertex(i, j).unwrap())?;
write!(f, "{weight:.6} ", weight = self.edges[i][j])?;
}
write!(f, "\n")?;
}