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"""
https://leetcode.com/explore/featured/card/march-leetcoding-challenge-2021/588/week-1-march-1st-march-7th/3663/
https://leetcode.com/problems/design-hashmap/
Design a HashMap without using any built-in hash table libraries.
To be specific, your design should include these functions:
put(key, value) : Insert a (key, value) pair into the HashMap. If the value already exists in the HashMap, update the value.
get(key): Returns the value to which the specified key is mapped, or -1 if this map contains no mapping for the key.
remove(key) : Remove the mapping for the value key if this map contains the mapping for the key.
Example:
MyHashMap hashMap = new MyHashMap();
hashMap.put(1, 1);
hashMap.put(2, 2);
hashMap.get(1); // returns 1
hashMap.get(3); // returns -1 (not found)
hashMap.put(2, 1); // update the existing value
hashMap.get(2); // returns 1
hashMap.remove(2); // remove the mapping for 2
hashMap.get(2); // returns -1 (not found)
Note:
All keys and values will be in the range of [0, 1000000].
The number of operations will be in the range of [1, 10000].
Please do not use the built-in HashMap library.
"""
from typing import List, Tuple
# Runtime: 204 ms, faster than 84.78% of Python3 online submissions for Design HashMap.
# Memory Usage: 17.6 MB, less than 52.06% of Python3 online submissions for Design HashMap.
class MyHashMap:
def __init__(self):
"""
Initialize your data structure here.
"""
self.hashtable = [[] for _ in range(1019)]
def hash(self, key: int) -> int:
return key % len(self.hashtable)
def bucket(self, key: int) -> List[List[int]]:
return self.hashtable[self.hash(key)]
def put(self, key: int, value: int) -> None:
"""
value will always be non-negative.
"""
b = self.bucket(key)
for p in b:
if p[0] == key:
p[1] = value
return
b.append([key, value])
def get(self, key: int) -> int:
"""
Returns the value to which the specified key is mapped, or -1 if this map contains no mapping for the key
"""
b = self.bucket(key)
for p in b:
if p[0] == key:
return p[1]
return -1
def remove(self, key: int) -> None:
"""
Removes the mapping of the specified value key if this map contains a mapping for the key
"""
b = self.bucket(key)
for p in b:
if p[0] == key:
b.remove(p)
return
# Your MyHashMap object will be instantiated and called as such:
# obj = MyHashMap()
# obj.put(key,value)
# param_2 = obj.get(key)
# obj.remove(key)
hashMap = MyHashMap()
hashMap.put(1, 1)
hashMap.put(2, 2)
print(hashMap.get(1)) # returns 1
print(hashMap.get(3)) # returns -1 (not found)
hashMap.put(2, 1) # update the existing value
print(hashMap.get(2)) # returns 1
hashMap.remove(2) # remove the mapping for 2
print(hashMap.get(2)) # returns -1 (not found)