981. Time Based Key-Value Store

Author: gzc

cpp/981-990/Time Based Key-Value Store.cpp

@@ -0,0 +1,31 @@
+class TimeMap {
+    unordered_map<string, vector<pair<int, string>>> db;
+public:
+    TimeMap() {
+        
+    }
+    
+    void set(string key, string value, int timestamp) {
+        db[key].push_back({timestamp, value});
+    }
+    
+    string get(string key, int timestamp) {
+        auto cmp = [](const pair<int, string>& lhs, const pair<int, string>& rhs) {
+            return lhs.first < rhs.first;
+        };
+        auto it = upper_bound(db[key].begin(), db[key].end(), make_pair(timestamp, ""), cmp);
+        if (it == db[key].begin()) {
+            return "";
+        } else {
+            it--;
+            return it->second;
+        }
+    }
+};
+
+/**
+ * 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);
+ */