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 ("").

Runtime: 212 ms, faster than 55.01% of C++ online submissions for Time Based Key-Value Store.

Memory Usage: 57 MB, less than 100.00% of C++ online submissions for Time Based Key-Value Store.

class TimeMap {
private:
unordered_map> mp;
vector tvec;
public:
/** Initialize your data structure here. */
TimeMap() {}

void set(string key, string value, int timestamp) {
mp[key][timestamp] = value;
}

string get(string key, int timestamp) {
if(!mp.count(key)) return "";
if(mp[key].count(timestamp)) return mp[key][timestamp];
for(auto it = mp[key].rbegin(); it != mp[key].rend(); it++) {
if(it->first > timestamp) continue;
else {
return it->second;
}
}
return "";
}
};