Uloha 7 hotova

u7/hash_table.py

@@ -0,0 +1,117 @@
+class HashTable:
+    def __init__(self, capacity=10):
+        if not isinstance(capacity, int) or isinstance(capacity, bool):
+            raise TypeError("Capacity must be an integer.")
+        if capacity <= 0:
+            raise ValueError("Capacity must be positive.")
+            
+        self.capacity = capacity
+        self.empty = object()
+        self.deleted = object()
+        self.slots = [self.empty] * capacity
+        self.count = 0
+
+    def hash(self, key):
+        if not isinstance(key, str):
+            raise TypeError("Key must be a string.")
+        
+        result = 0
+        for char in key:
+            result = result * 31 + ord(char)
+        return result % self.capacity
+
+    def probe(self, key):
+        start_idx = self.hash(key)
+        idx = start_idx
+        first_deleted = None
+        
+        for _ in range(self.capacity):
+            slot = self.slots[idx]
+            if slot is self.empty:
+                return first_deleted if first_deleted is not None else idx
+            elif slot is self.deleted:
+                if first_deleted is None:
+                    first_deleted = idx
+            elif slot[0] == key:
+                return idx
+            
+            idx = (idx + 1) % self.capacity
+            
+        if first_deleted is not None:
+            return first_deleted
+        raise RuntimeError("HashTable probe failed.")
+
+    def load_factor(self):
+        return float(self.count) / self.capacity
+
+    def __len__(self):
+        return self.count
+
+    def __contains__(self, key):
+        if not isinstance(key, str):
+            raise TypeError("Key must be a string.")
+        try:
+            idx = self.probe(key)
+            slot = self.slots[idx]
+            return slot is not self.empty and slot is not self.deleted and slot[0] == key
+        except RuntimeError:
+            return False
+
+    def __getitem__(self, key):
+        if not isinstance(key, str):
+            raise TypeError("Key must be a string.")
+        idx = self.probe(key)
+        slot = self.slots[idx]
+        if slot is not self.empty and slot is not self.deleted and slot[0] == key:
+            return slot[1]
+        raise KeyError(key)
+
+    def __setitem__(self, key, value):
+        if not isinstance(key, str):
+            raise TypeError("Key must be a string.")
+        
+        is_new = not self.__contains__(key)
+        if is_new:
+            if (self.count + 1) / self.capacity > 0.7:
+                self._resize()
+                
+        idx = self.probe(key)
+        slot = self.slots[idx]
+        
+        if slot is self.empty or slot is self.deleted:
+            self.slots[idx] = (key, value)
+            self.count += 1
+        elif slot[0] == key:
+            self.slots[idx] = (key, value)
+
+    def __delitem__(self, key):
+        if not isinstance(key, str):
+            raise TypeError("Key must be a string.")
+        idx = self.probe(key)
+        slot = self.slots[idx]
+        if slot is not self.empty and slot is not self.deleted and slot[0] == key:
+            self.slots[idx] = self.deleted
+            self.count -= 1
+        else:
+            raise KeyError(key)
+
+    def __iter__(self):
+        for slot in self.slots:
+            if slot is not self.empty and slot is not self.deleted:
+                yield slot[0]
+
+    def _resize(self):
+        old_slots = self.slots
+        self.capacity *= 2
+        self.slots = [self.empty] * self.capacity
+        self.count = 0
+        
+        for slot in old_slots:
+            if slot is not self.empty and slot is not self.deleted:
+                key, value = slot
+                idx = self.probe(key)
+                self.slots[idx] = (key, value)
+                self.count += 1
+
+
+