[Leetcode]981. Time Based Key-Value Store

3987 ワード

# [[Leetcode]981. Time Based Key-Value Store](https://leetcode.com/problems/time-based-key-value-store/) 
-難易度:Medium#Description
Create a timebased key-value store class  TimeMap , that supports two operations.
1.  set(string key, string value, int timestamp)
  • Stores the  key  and  value , along with the given  timestamp .

  • 2.  get(string key, int timestamp)
  • Returns a value such that  set(key, value, timestamp_prev) was called previously, with  timestamp_prev <= timestamp .
  • If there are multiple such values, it returns the one with the largest  timestamp_prev .
  • If there are no values, it returns the empty string ( "" ).

  •  
    Example 1:
    Input: inputs = ["TimeMap","set","get","get","set","get","get"], inputs = [[],["foo","bar",1],["foo",1],["foo",3],["foo","bar2",4],["foo",4],["foo",5]]
    Output: [null,null,"bar","bar",null,"bar2","bar2"]
    Explanation:   
    TimeMap kv;   
    kv.set("foo", "bar", 1); // store the key "foo" and value "bar" along with timestamp = 1   
    kv.get("foo", 1);  // output "bar"   
    kv.get("foo", 3); // output "bar" since there is no value corresponding to foo at timestamp 3 and timestamp 2, then the only value is at timestamp 1 ie "bar"   
    kv.set("foo", "bar2", 4);   
    kv.get("foo", 4); // output "bar2"   
    kv.get("foo", 5); //output "bar2"   
    
    

    Example 2:
    Input: inputs = ["TimeMap","set","set","get","get","get","get","get"], inputs = [[],["love","high",10],["love","low",20],["love",5],["love",10],["love",15],["love",20],["love",25]]
    Output: [null,null,null,"","high","high","low","low"]
    

     
    Note:
  • All key/value strings are lowercase.
  • All key/value strings have length in the range  [1, 100]
  • The  timestamps  for all  TimeMap.set  operations are strictly increasing.
  • 1 <= timestamp <= 10^7
  • TimeMap.set  and  TimeMap.get  functions will be called a total of  120000  times (combined) per test case.

  • 私のコード``python
    import heapq
    class TimeMap:     def __init__(self):         """        Initialize your data structure here.         """        self.Stores = {}
        def set(self, key: str, value: str, timestamp: int) -> None:         tmp = self.Stores.get(key, [])         heapq.heappush(tmp,[timestamp, value])         self.Stores[key] = tmp
        def get(self, key: str, timestamp: int) -> str:         nums = self.Stores.get(key, [])
            if len(nums) == 0 or nums[0][0]>timestamp:             return ""
            left = 0         right = len(nums) - 1         mid = (left + right)//2         while (left < right):             if nums[mid][0] == timestamp or (                         mid < len(nums) - 1 and nums[mid][0] < timestamp and nums[mid + 1][0] > timestamp):                 return nums[mid][1]             if nums[mid][0] < timestamp:                 left = mid + 1             else:                 right = mid - 1             mid = (left + right)//2         if mid == len(nums) - 1 and nums[mid][0] <= timestamp:             return nums[mid][1]         return ""
    ```