feat: 705_design_hashset

705_design_hashset/Cargo.lock

@@ -0,0 +1,7 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 4
+
+[[package]]
+name = "design_hashset"
+version = "0.1.0"

705_design_hashset/Cargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "design_hashset"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]

705_design_hashset/src/lib.rs

@@ -0,0 +1,47 @@
+use std::hash::{DefaultHasher, Hash, Hasher};
+
+pub struct MyHashSet {
+    capacity: usize,
+    buckets: Vec<Vec<i32>>,
+}
+
+impl MyHashSet {
+    pub fn new() -> Self {
+        const CAPACITY: usize = 4096;
+        Self {
+            capacity: CAPACITY,
+            buckets: vec![Vec::new(); CAPACITY],
+        }
+    }
+
+    pub fn add(&mut self, key: i32) {
+        let index = self.get_bucket_index(key);
+        let list = self.buckets.get_mut(index).unwrap();
+
+        if list.iter().find(|num| **num == key).is_none() {
+            list.push(key);
+        }
+    }
+
+    pub fn remove(&mut self, key: i32) {
+        let index = self.get_bucket_index(key);
+        let list = self.buckets.get_mut(index).unwrap();
+
+        if let Some(index_to_remove) = list.iter().position(|num| *num == key) {
+            list.remove(index_to_remove);
+        }
+    }
+
+    pub fn contains(&self, key: i32) -> bool {
+        let index = self.get_bucket_index(key);
+        let list = self.buckets.get(index).unwrap();
+
+        list.iter().find(|num| **num == key).is_some()
+    }
+
+    fn get_bucket_index(&self, key: impl Hash) -> usize {
+        let mut hasher = DefaultHasher::new();
+        key.hash(&mut hasher);
+        (hasher.finish() as usize) & (self.capacity - 1)
+    }
+}