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63 changes: 63 additions & 0 deletions Design HashSet.py
Original file line number Diff line number Diff line change
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# Time Complexity: O(1) for add, remove, and contains
# Space Complexity: O(1), because the maximum key range is fixed
# Did this code successfully run on LeetCode: Yes

class MyHashSet(object):

def __init__(self):
self.primaryBuckets = 1000
self.secondaryBuckets = 1000
self.storage = [None] * self.primaryBuckets

def getPrimaryHash(self, key):
return key % self.primaryBuckets

def getSecondaryHash(self, key):
return key // self.secondaryBuckets


def add(self, key):
"""
:type key: int
:rtype: None
"""
primaryHash = self.getPrimaryHash(key)
if self.storage[primaryHash] == None:
if primaryHash == 0:
self.storage[primaryHash] = [False] * (self.secondaryBuckets + 1)
else:
self.storage[primaryHash] = [False] * self.secondaryBuckets
secondaryHash = self.getSecondaryHash(key)
self.storage[primaryHash][secondaryHash] = True


def remove(self, key):
"""
:type key: int
:rtype: None
"""
primaryHash = self.getPrimaryHash(key)
if self.storage[primaryHash] is None:
return
secondaryHash = self.getSecondaryHash(key)
self.storage[primaryHash][secondaryHash] = False


def contains(self, key):
"""
:type key: int
:rtype: bool
"""
primaryHash = self.getPrimaryHash(key)
if self.storage[primaryHash] is None:
return False
secondaryHash = self.getSecondaryHash(key)
return self.storage[primaryHash][secondaryHash]


# Your MyHashSet object will be instantiated and called as such:
obj = MyHashSet()
obj.add(1)
obj.add(2)
obj.remove(1)
print(obj.contains(1))
55 changes: 55 additions & 0 deletions MinStack.py
Original file line number Diff line number Diff line change
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# Time Complexity: O(1) for push, pop, top, and getMin
# Space Complexity: O(n)

# Did this code successfully run on LeetCode: Yes

class MinStack(object):

def __init__(self):
self.st, self.minSt = [], []
self.min = float("inf")


def push(self, value):
"""
:type value: int
:rtype: None
"""
if value <= self.min:
self.minSt.append(self.min)
self.min = value
self.st.append(value)



def pop(self):
"""
:rtype: None
"""
if self.min == self.st.pop():
self.min = self.minSt.pop()


def top(self):
"""
:rtype: int
"""
return self.st[-1]


def getMin(self):
"""
:rtype: int
"""
return self.min



# Your MinStack object will be instantiated and called as such:
obj = MinStack()
obj.push(2)
obj.push(1)
obj.push(4)
obj.pop()
print(obj.top())
print(obj.getMin())