still broken !
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SHA256:JyLeVWE4bF3tDnFeUpUaJsPsNlJyBldDGV/dIKSLyN8
1 changed files with 61 additions and 96 deletions
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@ -42,18 +42,23 @@ impl Ord for Edge {
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pub struct Graph {
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pub size: usize,
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pub edges: Vec<Edge>,
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pub edges: Vec<Vec<f64>>,
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}
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impl Graph {
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pub fn new(size: usize) -> Self {
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Self {
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size,
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edges: (0..size).map(|u|
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(0..size).map(|v|
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Edge { src: u, dst: v, weight: 0.0 }
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).collect::<Vec<_>>()
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).flatten()
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// edges: (0..size).map(|u|
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// (0..size).map(|v|
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// Edge { src: u, dst: v, weight: 0.0 }
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// ).collect::<Vec<_>>()
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// ).flatten()
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// .collect::<Vec<_>>(),
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edges: (0..size)
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.map(|_| (0..size)
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.map(|_| 0.0)
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.collect::<Vec<_>>())
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.collect::<Vec<_>>(),
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}
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}
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@ -63,112 +68,71 @@ impl Graph {
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size,
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edges: (0..size).map(|u|
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(0..size).map(|v|
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Edge {
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src: u,
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dst: v,
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weight: if u == v { 0.0 }
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if u == v { 0.0 }
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else { thread_rng().gen::<f64>() }
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}
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).collect::<Vec<_>>()
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).flatten()
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).collect::<Vec<_>>())
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.collect::<Vec<_>>(),
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}
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}
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pub fn vertex(&self, u: usize, v: usize) -> Option<f64> {
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if u >= self.size || v >= self.size {
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return None;
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}
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Some(self.edges.iter().find(|e| e.src == u && e.dst == v).unwrap().weight)
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pub fn edges(&self) -> Vec<Edge> {
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(0..self.size)
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.map(|i|
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(0..self.size)
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.map(|j| Edge {
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src: i,
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dst: j,
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weight: self.edges[i][j],
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})
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.collect::<Vec<_>>()
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)
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.flatten()
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.collect::<Vec<_>>()
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}
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pub fn prim(&self) -> Vec<Edge> {
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// 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.
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let mut min_edges = (0..self.size)
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.map(|i|
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*self.edges.iter()
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.filter(|e| (e.src == i || e.dst == i) && e.src != e.dst)
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.min()
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.unwrap()
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).collect::<Vec<_>>();
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// dbg!(&min_edges);
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let mut parent = vec![0; self.size];
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// helper struct for the queue
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#[derive(Clone, Debug)]
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struct Vertex {
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index: usize,
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min_weight: f64,
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}
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let mut key = vec![f64::INFINITY; self.size];
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impl Hash for Vertex {
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fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
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self.index.hash(state);
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let mut mst_set = vec![false; self.size];
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key[0] = 0.0;
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parent[0] = usize::MAX;
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for _ in 0..(self.size - 1) {
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let u = {
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let mut min_index = 0;
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let mut min = f64::MAX;
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for k in 0..self.size {
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if mst_set[k] == false && key[k] < min {
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min = key[k];
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min_index = k;
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}
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}
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impl PartialEq for Vertex {
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fn eq(&self, other: &Self) -> bool {
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self.min_weight == other.min_weight
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}
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}
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min_index
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};
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impl Eq for Vertex {}
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mst_set[u] = true;
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impl PartialOrd for Vertex {
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fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
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self.min_weight.partial_cmp(&other.min_weight)
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}
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}
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impl Ord for Vertex {
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fn cmp(&self, other: &Self) -> Ordering {
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self.min_weight.total_cmp(&other.min_weight)
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}
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}
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// Initialize an empty forest F
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let mut forest = vec![];
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// and a set Q of vertices
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let mut queue = BinaryHeap::<Reverse<Vertex>>::new();
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// that have not yet been included in F (initially, all vertices).
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(0..self.size)
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.map(|i| Vertex { index: i, min_weight: min_edges[i].weight })
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.for_each(|v| queue.push(Reverse(v)));
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// Repeat the following steps until Q is empty:
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// Find and remove a vertex v from Q having the minimum possible value of C[v]
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while let Some(Reverse(v)) = queue.pop() {
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// Add v to F
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forest.push(v.clone());
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// Loop over the edges vw connecting v to other vertices w.
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for vw in self.edges.iter()
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.filter(|e| (e.src == v.index || e.dst == v.index) && e.src != e.dst) {
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// the vertex in the current edge that isn't v.src
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let w = if vw.src == v.index { vw.dst } else { vw.src };
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// For each such edge, if w still belongs to Q and vw has smaller weight than C[w], perform the following steps:
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if queue.clone().iter().any(|Reverse(e)| e.index == w || e.index == w) && vw.weight < min_edges[w].weight {
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dbg!(&w);
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// Set C[w] to the cost of edge vw
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// Set E[w] to point to edge vw.
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min_edges[w] = *vw;
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for v in 0..self.size {
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let w = self.edges[u][v];
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if u != v && mst_set[v] == false && w < key[v] {
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parent[v] = u;
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key[v] = w;
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}
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}
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}
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// dbg!(&min_edges);
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// Return F, which specifically includes the corresponding edges in E
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forest.iter()
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.map(|i| min_edges[i.index])
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// deduplication
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.collect::<HashSet<_>>()
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.iter()
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.map(|e| *e)
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.collect::<Vec<_>>()
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(1..self.size)
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.map(|i| Edge {
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src: parent[i],
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dst: i,
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weight: self.edges[i][parent[i]],
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})
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.collect()
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}
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fn find_id(belongs: &mut Vec<usize>, i: usize) -> usize {
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@ -194,7 +158,8 @@ impl Graph {
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}
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pub fn kruskal(&self) -> Vec<Edge> {
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let mut edges = self.edges.iter()
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let edges = self.edges();
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let mut edges = edges.iter()
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.filter(|e| e.weight != 0.0)
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.collect::<Vec<_>>();
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@ -224,7 +189,7 @@ impl Display for Graph {
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fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
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for i in 0..self.size {
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for j in 0..self.size {
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write!(f, "{weight:.6} ", weight = self.vertex(i, j).unwrap())?;
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write!(f, "{weight:.6} ", weight = self.edges[i][j])?;
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}
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write!(f, "\n")?;
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}
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