committed from zkp

pythonkd · pythonkd · commit 158fe01c9697 · 2018-12-06T21:37:28.000+08:00
diff --git a/LeetCode/hashtable.py b/LeetCode/hashtable.py
@@ -0,0 +1,95 @@
+class Array(object):
+    def __init__(self, size=30, init=None):
+        self.size = size
+        self.items = [init]*size
+    def __getitem__(self, index):
+        return self.items[index]
+    def __setitem__(self, index, value):
+        self.items[index] = value
+    def __len__(self):
+        return self.size
+    def clear(self):
+        for i in range(len(self.size)):
+            self.items[i] = init
+    def __iter__(self):
+        for i in self.items:
+            yield i
+class Slot(object):
+    def __init__(self, value=None, key=None):
+        self.key, self.value = key, value
+class HashTable(object):
+    EMPTY = None
+    UNUSED = None
+    def __init__(self):
+        self._table = Array(20, HashTable.UNUSED)
+        self.length = 0
+    @property
+    def _load_factor(self):
+        return self.length / len(self._table)
+    def __len__(self):
+        return self.length
+    def _hash(self, key):
+        return abs(hash(key)%len(self._table))
+    def _find_key(self, key):
+        index = self._hash(key)
+        _len = self.length
+        while self._table[index] is not HashTable.UNUSED:
+            if self._table[index] is HashTable.EMPTY:
+                index = (index*5 +1) % _len
+                continue
+            elif self._table[index].key == key:
+                return index
+            else:
+                index = (index *5 + 1) / _len
+        return None
+    def _slot_can_insert(self, index):
+        return (self._table[index] is HashTable.EMPTY or HashTable.UNUSED)
+    def _find_slots_for_insert(self, key):
+        index = self._hash(key)
+        _len = self.length
+        while not _slot_can_insert(index):
+            index = (index*5 +1)%_len
+        return index
+    def __contains__(self, key):
+        index = _find_key(key)
+        return index is not None
+    def add(self, key, value):
+        if key in self:
+            index = self._find_key(key)
+            self._table[index].value = value
+            return False
+        else:
+            index = _find_slots_for_insert(key)
+            self._table[index] = Slot(value, key)
+            self.length += 1
+            if self._load_factor() >= 0.8:
+                self._rehash()
+            return True
+    def rehash(self):
+        old_table = self._table
+        newsize = len(self) * 2
+        self._table = Array(newsize, HashTable.UNUSED)
+        self.length = 0
+        for slot in old_table:
+            if slot is not HashTable.UNUSED and slot is not HashTable.EMPTY:
+                index = self._find_slots_for_insert(slot.key)
+                self._table[index] = slot
+                self.length += 1
+    def get(self, key, default=None):
+        index = self._find_key(key)
+        if index is None:
+            return default
+        else:
+            return self._table[index].value
+    def remove(self, key):
+        index = self._find_key(key)
+        if index is None:
+            raise KeyError()
+        value = self._table[index].value
+        self._table[index].key = HashTable.EMPTY
+        self.length -= 1
+        return value
+    def __iter__(self):
+        for slot in self._table:
+            if slot not in (HashTable.EMPTY, HashTable.UNUSED):
+                yield slot.key
