design-hashmap py3

0817_design-hashmap/python3/solution.py

@@ -0,0 +1,61 @@
+# Time: O(N / K) ; N is num of all keys and K is num of predefined buckets
+# Space: O(K + M) ; K is num of predefined buckets and M is no. of unique
+#        keys inserted
+
+from collections import deque
+
+class MyHashMap:
+    def __init__(self):
+        # TODO: Better hash function and better initial capacity needed
+        # Maybe initial capacity can even be passed as an option?
+        self.store = [Bucket()] * 997
+
+    def put(self, key: int, value: int) -> None:
+        i = self._hash(key)
+        
+        self.store[i].upsert(key, value)
+
+    def get(self, key: int) -> int:
+        i = self._hash(key)
+        
+        pair = self.store[i].get_pair(key)
+        
+        return pair[1] if pair else -1
+
+    def remove(self, key: int) -> None:
+        i = self._hash(key)
+        return self.store[i].remove(key)
+        
+    def _hash(self, key: int):
+        # TODO: Note down better hash functions
+        return key % 997
+        
+class Bucket:
+    def __init__(self):
+        self.d = deque()
+        
+    def upsert(self, key, value):
+        pair = self.get_pair(key)
+        
+        if pair is not None:
+            pair[1] = value
+        else:
+            self.d.append([key, value])
+        
+    def get_pair(self, key):
+        for item in self.d:
+            if item[0] == key:
+                return item
+    
+    def remove(self, key):
+        item = self.get_pair(key)
+        
+        if item is not None:
+            self.d.remove(item)
+
+
+# Your MyHashMap object will be instantiated and called as such:
+# obj = MyHashMap()
+# obj.put(key,value)
+# param_2 = obj.get(key)
+# obj.remove(key)