From ea8fd35c8ab5b2e8ed3ce8f9fc4ef3ffdf26fc76 Mon Sep 17 00:00:00 2001
From: SquidSpirit <squid@squidspirit.com>
Date: Sun, 21 Sep 2025 21:33:50 +0800
Subject: [PATCH] feat: 3508_implement_router

---
 3508_implement_router/Cargo.lock |  7 +++
 3508_implement_router/Cargo.toml |  6 +++
 3508_implement_router/src/lib.rs | 79 ++++++++++++++++++++++++++++++++
 3 files changed, 92 insertions(+)
 create mode 100644 3508_implement_router/Cargo.lock
 create mode 100644 3508_implement_router/Cargo.toml
 create mode 100644 3508_implement_router/src/lib.rs

diff --git a/3508_implement_router/Cargo.lock b/3508_implement_router/Cargo.lock
new file mode 100644
index 0000000..e81ff3b
--- /dev/null
+++ b/3508_implement_router/Cargo.lock
@@ -0,0 +1,7 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 4
+
+[[package]]
+name = "implement_router"
+version = "0.1.0"
diff --git a/3508_implement_router/Cargo.toml b/3508_implement_router/Cargo.toml
new file mode 100644
index 0000000..1fc462d
--- /dev/null
+++ b/3508_implement_router/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "implement_router"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
diff --git a/3508_implement_router/src/lib.rs b/3508_implement_router/src/lib.rs
new file mode 100644
index 0000000..7b12fcd
--- /dev/null
+++ b/3508_implement_router/src/lib.rs
@@ -0,0 +1,79 @@
+use std::collections::{HashMap, HashSet, VecDeque};
+
+#[derive(Clone, Copy, PartialEq, Eq, Hash)]
+pub struct Packet {
+    source: i32,
+    destination: i32,
+    timestamp: i32,
+}
+
+pub struct Router {
+    limit: usize,
+    set: HashSet<Packet>,
+    queue: VecDeque<Packet>,
+    dest_map: HashMap<i32, VecDeque<Packet>>,
+}
+
+impl Router {
+    pub fn new(memory_limit: i32) -> Self {
+        Self {
+            limit: memory_limit as usize,
+            set: HashSet::with_capacity(memory_limit as usize),
+            queue: VecDeque::with_capacity(memory_limit as usize),
+            dest_map: HashMap::new(),
+        }
+    }
+
+    pub fn add_packet(&mut self, source: i32, destination: i32, timestamp: i32) -> bool {
+        let packet = Packet {
+            source,
+            destination,
+            timestamp,
+        };
+
+        if self.set.contains(&packet) {
+            return false;
+        }
+
+        if self.limit <= self.queue.len() {
+            let popped_packet = self.queue.pop_front().unwrap();
+            self.set.remove(&popped_packet);
+            self.dest_map
+                .get_mut(&popped_packet.destination)
+                .unwrap()
+                .pop_front();
+        }
+
+        self.set.insert(packet);
+        self.queue.push_back(packet);
+        self.dest_map
+            .entry(packet.destination)
+            .or_insert(VecDeque::new())
+            .push_back(packet);
+
+        true
+    }
+
+    pub fn forward_packet(&mut self) -> Vec<i32> {
+        if let Some(packet) = self.queue.pop_front() {
+            self.set.remove(&packet);
+            self.dest_map
+                .get_mut(&packet.destination)
+                .unwrap()
+                .pop_front();
+            vec![packet.source, packet.destination, packet.timestamp]
+        } else {
+            vec![]
+        }
+    }
+
+    pub fn get_count(&self, destination: i32, start_time: i32, end_time: i32) -> i32 {
+        if let Some(packets) = self.dest_map.get(&destination) {
+            let start_index = packets.partition_point(|packet| packet.timestamp < start_time);
+            let end_index = packets.partition_point(|packet| packet.timestamp <= end_time);
+            (end_index - start_index) as i32
+        } else {
+            0
+        }
+    }
+}