文巾解题 981. 基于时间的键值存储

Posted 2021-08-08 刘文巾

1 题目描述

、

 2 解题思路

创建两个字典，它们有相同的键，键值分别是value和timestamp

然后get的时候，我先用二分查找最大的timestamp_prev的下标，然后用这个下标定位到相应的value值

class TimeMap(object):

    def __init__(self):
        """
        Initialize your data structure here.
        """
        self.dit_v=dict()
#key——value
        self.dit_t=dict()
#key——timestamp

    def set(self, key, value, timestamp):
        """
        :type key: str
        :type value: str
        :type timestamp: int
        :rtype: None
        """
        if(key in self.dit_v):
            self.dit_v[key].append(value)
            self.dit_t[key].append(timestamp)
        else:
            self.dit_v[key]=[value]
            self.dit_t[key]=[timestamp]
        

    def get(self, key, timestamp):
        """
        :type key: str
        :type timestamp: int
        :rtype: str
        """
        if(key not in self.dit_v):
            return("")
#字典中没有这个键值

        value=self.dit_v[key]
        time=self.dit_t[key]

        left=0
        right=len(value)-1
        while(left<=right):
            mid=(right-left)//2+left
            if(time[mid]==timestamp):
                return(value[mid])
            elif(time[mid]>timestamp):
                right=mid-1
            elif(time[mid]<timestamp):
                left=mid+1
#二分查找

        if(right==-1):
            return("")  
        return value[right]


# Your TimeMap object will be instantiated and called as such:
# obj = TimeMap()
# obj.set(key,value,timestamp)
# param_2 = obj.get(key,timestamp)