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renamed seen to visited in dijkstras and changed to MinHeap

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specCon18 2024-05-19 01:48:02 -04:00
parent 3a028dfdf2
commit 42a2375e81
1 changed files with 16 additions and 18 deletions
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26
src/dijkstras.rs
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@ -1,8 +1,8 @@
use crate::data_structures::WeightedAdjacencyList; use crate::data_structures::{WeightedAdjacencyList,MinHeap};
#[cfg(test)] #[cfg(test)]
mod tests { mod tests {
use crate::data_structures::WeightedAdjacencyList; use crate::data_structures::WeightedAdjacencyList;
use super::{dijkstras_shortest_path,}; use super::dijkstras_shortest_path;
#[test] #[test]
fn dijkstras_shortest_path_primeagen_class_test(){ fn dijkstras_shortest_path_primeagen_class_test(){
// (1) --- (4) ---- (5) // (1) --- (4) ---- (5)
@ -43,27 +43,26 @@ mod tests {
assert_eq!(path.unwrap(), vec![0, 1, 4, 5]); assert_eq!(path.unwrap(), vec![0, 1, 4, 5]);
} }
} }
pub fn dijkstras_shortest_path(
source: usize, pub fn dijkstras_shortest_path( source: usize, sink: usize, graph: WeightedAdjacencyList<usize, usize>) -> Option<Vec<usize>> {
sink: usize, let mut visited: MinHeap<(f64, usize)> = MinHeap::new();
graph: WeightedAdjacencyList<usize, usize>,
) -> Option<Vec<usize>> {
let mut seen: Vec<bool> = vec![false; graph.len()];
let mut prev: Vec<usize> = vec![usize::MAX; graph.len()]; let mut prev: Vec<usize> = vec![usize::MAX; graph.len()];
let mut dists: Vec<f64> = vec![f64::INFINITY; graph.len()]; let mut dists: Vec<f64> = vec![f64::INFINITY; graph.len()];
dists[source] = 0.0; dists[source] = 0.0;
visited.push((0.0, source));
while let Some((_, curr)) = visited.pop() {
if curr == sink {
break; // found shortest path to sink
}
while has_unvisited(&seen, &dists) {
let curr = get_lowest_unvisited(&seen, &dists);
seen[curr] = true;
if let Some(adjs) = graph.get_neighbors(&curr) { if let Some(adjs) = graph.get_neighbors(&curr) {
for (&to, &weight) in adjs.iter() { for (&to, &weight) in adjs.iter() {
if !seen[to] {
let new_dist = dists[curr] + weight as f64; let new_dist = dists[curr] + weight as f64;
if new_dist < dists[to] { if new_dist < dists[to] {
dists[to] = new_dist; dists[to] = new_dist;
prev[to] = curr; prev[to] = curr;
} visited.push((new_dist, to));
} }
} }
} }
@ -84,7 +83,6 @@ pub fn dijkstras_shortest_path(
path.reverse(); path.reverse();
Some(path) Some(path)
} }
fn has_unvisited(seen: &[bool], dists: &[f64]) -> bool { fn has_unvisited(seen: &[bool], dists: &[f64]) -> bool {
seen.iter().enumerate().any(|(i, &s)| !s && dists[i] < f64::INFINITY) seen.iter().enumerate().any(|(i, &s)| !s && dists[i] < f64::INFINITY)
} }