problems(rs): add “1376. Time Needed to Inform All Employees”

Signed-off-by: Matej Focko <mfocko@redhat.com>

problems/rs/time-needed-to-inform-all-employees.rs

@@ -0,0 +1,37 @@
+use std::collections::{HashMap, HashSet, VecDeque};
+
+impl Solution {
+    fn from_managers(managers: &[i32]) -> HashMap<usize, HashSet<usize>> {
+        let mut mapping = HashMap::new();
+
+        for (i, manager) in managers
+            .iter()
+            .enumerate()
+            .filter(|&(_, &manager)| manager != -1)
+        {
+            mapping
+                .entry(*manager as usize)
+                .or_insert_with(HashSet::new)
+                .insert(i);
+        }
+
+        mapping
+    }
+
+    pub fn num_of_minutes(_n: i32, head_id: i32, manager: Vec<i32>, inform_time: Vec<i32>) -> i32 {
+        let manager_mapping = Solution::from_managers(&manager);
+
+        let mut q = VecDeque::new();
+        q.push_back((head_id as usize, 0));
+
+        let mut minutes = -1;
+        while let Some((manager, t)) = q.pop_front() {
+            minutes = std::cmp::max(minutes, t);
+
+            for employee in manager_mapping.get(&manager).unwrap_or(&HashSet::new()) {
+                q.push_back((*employee, t + inform_time[manager]));
+            }
+        }
+        minutes
+    }
+}