85 lines
3.0 KiB
C++
85 lines
3.0 KiB
C++
// Source : https://leetcode.com/problems/time-based-key-value-store/
|
|
// Author : Hao Chen
|
|
// Date : 2019-01-30
|
|
|
|
/*****************************************************************************************************
|
|
*
|
|
* Create a timebased key-value store class Timeap, 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 = ["Timeap","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:
|
|
* Timeap 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 = ["Timeap","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 Timeap.set operations are strictly increasing.
|
|
* 1 <= timestamp <= 107
|
|
* Timeap.set and Timeap.get functions will be called a total of 120000 times (combined) per
|
|
* test case.
|
|
******************************************************************************************************/
|
|
|
|
class TimeMap {
|
|
private:
|
|
unordered_map<string, std::set<int>> key_time;
|
|
unordered_map<int, string> time_value;
|
|
public:
|
|
/** Initialize your data structure here. */
|
|
TimeMap() {
|
|
|
|
}
|
|
|
|
void set(string key, string value, int timestamp) {
|
|
key_time[key].insert(timestamp);
|
|
time_value[timestamp] = value;
|
|
}
|
|
|
|
string get(string key, int timestamp) {
|
|
if ( key_time.find(key) == key_time.end() ) return "";
|
|
auto it = key_time[key].lower_bound(timestamp);
|
|
if ( *it == timestamp ) return time_value[*it];
|
|
if ( it != key_time[key].begin() ) {
|
|
it--;
|
|
return time_value[*it];
|
|
}
|
|
return "";
|
|
}
|
|
};
|
|
|
|
|
|
/**
|
|
* Your TimeMap object will be instantiated and called as such:
|
|
* TimeMap* obj = new TimeMap();
|
|
* obj->set(key,value,timestamp);
|
|
* string param_2 = obj->get(key,timestamp);
|
|
*/
|