1+ """
2+ Design HashMap
3+
4+ Design a HashMap without using any built-in hash table libraries.
5+
6+ Implement the MyHashMap class:
7+
8+ - MyHashMap() initializes the object with an empty map.
9+ - void put(int key, int value) inserts a (key, value) pair into the HashMap.
10+ If the key already exists in the map, update the corresponding value.
11+ - int get(int key) returns the value to which the specified key is mapped,
12+ or -1 if this map contains no mapping for the key.
13+ - void remove(key) removes the key and its corresponding value if the map
14+ contains the mapping for the key.
15+
16+ Example 1:
17+
18+ Input:
19+ ["MyHashMap", "put", "put", "get", "get", "put", "get", "remove", "get"]
20+ [[], [1, 1], [2, 2], [1], [3], [2, 1], [2], [2], [2]]
21+
22+ Output:
23+ [null, null, null, 1, -1, null, 1, null, -1]
24+
25+ Explanation:
26+ MyHashMap myHashMap = new MyHashMap();
27+ myHashMap.put(1, 1); # The map is now [[1,1]]
28+ myHashMap.put(2, 2); # The map is now [[1,1], [2,2]]
29+ myHashMap.get(1); # return 1
30+ myHashMap.get(3); # return -1 (not found)
31+ myHashMap.put(2, 1); # update the existing value -> [[1,1], [2,1]]
32+ myHashMap.get(2); # return 1
33+ myHashMap.remove(2); # remove the mapping for 2 -> [[1,1]]
34+ myHashMap.get(2); # return -1 (not found)
35+
36+ Constraints:
37+ 0 <= key, value <= 1,000,000
38+ At most 10,000 calls will be made to put, get, and remove.
39+ """
40+ 41+ # Method 1:
42+ class MyHashMap :
43+ 44+ def __init__ (self ):
45+ self .size = 1000001
46+ self .data = [- 1 for _ in range (self .size )]
47+ 48+ def put (self , key : int , value : int ) -> None :
49+ self .data [key ] = value
50+ 51+ def get (self , key : int ) -> int :
52+ return self .data [key ]
53+ 54+ def remove (self , key : int ) -> None :
55+ self .data [key ] = - 1
56+ 57+ # Method 2:
58+ class MyHashMap :
59+ 60+ def __init__ (self ):
61+ self .size = 10000
62+ self .data = [[] for _ in range (self .size )]
63+ 64+ def calculate_hash_value (self ,key : int ):
65+ return key % self .size
66+ 67+ def put (self , key : int , value : int ) -> None :
68+ hv = self .calculate_hash_value (key )
69+ for i , (k ,v ) in enumerate (self .data [hv ]):
70+ if k == key :
71+ self .data [hv ][i ] = (key ,value )
72+ return
73+ self .data [hv ].append ((key ,value ))
74+ 75+ def get (self , key : int ) -> int :
76+ hv = self .calculate_hash_value (key )
77+ for k ,v in self .data [hv ]:
78+ if k == key :
79+ return v
80+ return - 1
81+ 82+ def remove (self , key : int ) -> None :
83+ hv = self .calculate_hash_value (key )
84+ self .data [hv ] = [(k ,v ) for (k ,v ) in self .data [hv ] if k != key ]
85+
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