Anul 3 Semestrul 1

Anul 3/Semestrul 1/Formal Languages and Compiler Design/Hashtable.py

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+import copy
+
+
+class Node:
+    def __init__(self, key, value):
+        self.key = key
+        self.value = value
+        self.next = None
+
+
+class HashTable:
+    def __init__(self):
+        self.capacity = 2
+        self.noOfElements = 0
+        self.elementList = [None] * 2
+    
+    def hash(self, value):
+        if isinstance(value, int):
+            return value % self.capacity
+        
+        sum = 0
+        for l in value:
+            sum += ord(l)
+        return sum % self.capacity
+
+    def insert(self, key, value):
+        if self.noOfElements and (self.capacity // self.noOfElements < 2):
+            self.resizeAndRehash()
+        hash_key = self.hash(key)
+        element = self.elementList[hash_key]
+        
+        if element is None:
+            self.elementList[hash_key] = Node(key, value)
+            self.noOfElements += 1
+            return
+        
+        while element.next is not None:
+            element = element.next
+        element.next = Node(key, value)
+        self.noOfElements += 1
+        
+    def get(self, key):
+        element = self.elementList[self.hash(key)]
+        while element is not None:
+            if element.key == key:
+                return element.value
+            element = element.next
+        return None
+    
+    def getPosition(self, key):
+        element = self.elementList[self.hash(key)]
+        position = 0
+        while element is not None:
+            if element.key == key:
+                return (key,position)
+            element = element.next
+            position += 1
+        return None
+    
+    def resizeAndRehash(self):
+        self.capacity *= 2
+        
+        copyElementList = copy.deepcopy(self.elementList)
+        self.elementList = [None] * self.capacity
+        self.noOfElements = 0
+        for element in copyElementList:
+            copyElement = copy.deepcopy(element)
+            while copyElement is not None:
+                self.insert(copyElement.key, copyElement.value)
+                copyElement = copyElement.next
+    
+    def __str__(self):
+        var = ""
+        for element in self.elementList:
+            while element is not None:
+                var += f"{element.key} -> {element.value}\n"
+                element = element.next
+        return var