network time

Author: jhideki

src/main.rs

@@ -1,2 +1,2 @@
-mod coin_change2;
+mod shortestnetworkpath;
 fn main() {}

src/shortestnetworkpath.rs

@@ -0,0 +1,64 @@
+use std::cmp::min;
+
+pub struct Solution {}
+
+impl Solution {
+    pub fn network_delay_time(times: Vec<Vec<i32>>, n: i32, k: i32) -> i32 {
+        use std::cmp::Reverse;
+        use std::collections::BinaryHeap;
+        use std::collections::HashMap;
+        use std::collections::HashSet;
+
+        #[derive(PartialEq, Eq, PartialOrd, Ord)]
+        pub struct Edge {
+            weight: i32,
+            node: i32,
+        }
+
+        let mut visited: HashSet<i32> = HashSet::new();
+        let mut edges: HashMap<i32, Vec<Edge>> = HashMap::new();
+
+        for val in times {
+            let (u, v, w) = (val[0], val[1], val[2]);
+
+            let edge = Edge { weight: w, node: v };
+
+            if edges.contains_key(&u) {
+                edges.entry(u).and_modify(|val| val.push(edge));
+            } else {
+                edges.insert(u, vec![edge]);
+            }
+        }
+
+        let mut min_heap: BinaryHeap<Reverse<Edge>> = BinaryHeap::new();
+        let mut res = 0;
+
+        min_heap.push(Reverse(Edge { weight: 0, node: k }));
+
+        while !min_heap.is_empty() {
+            let edge = min_heap.pop().unwrap().0;
+
+            if visited.contains(&edge.node) {
+                continue;
+            }
+            visited.insert(edge.node);
+            res = edge.weight;
+
+            if let Some(edges) = edges.get(&edge.node) {
+                for e in edges {
+                    if !visited.contains(&e.node) {
+                        min_heap.push(Reverse(Edge {
+                            weight: e.weight + res,
+                            node: e.node,
+                        }));
+                    }
+                }
+            }
+        }
+
+        if res == 0 || visited.len() != n as usize {
+            return -1;
+        }
+        res
+    }
+}