题目：
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.
分析：
。。。。
代码：
class MyHashMap:
def __init__(self):
"""
Initialize your data structure here.
"""
self.data = {}
def put(self, key: int, value: int) -> None:
"""
value will always be non-negative.
"""
if value < 0 or key < 0 or key > 1000000:
return None
self.data[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
"""
if key in self.data.keys():
return self.data[key]
else:
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
"""
if key in self.data.keys():
self.data.pop(key)
