leetcode

Author: ayoubzulfiqar

README.md

@@ -73,6 +73,7 @@ This repo contain leetcode solution using DART and GO programming language. Most
 - [Minimum Time to Make Rope Colorful](MinimumTimeToMakeRopeColorful/minimum_time_to_make_rope_colorful.dart)
 - [Isomorphic Strings](IsomorphicStrings/isomorphic_strings.dart)
 - [Add One Row to Tree](AddOneRowToTree/add_one_row_to_tree.dart)
+- [Time Based Key-Value Store](TimeBasedKeyValueStore/time_based_key_value_store.dart)
 
 ## Reach me via
 

TimeBasedKeyValueStore/time_based_key_value_store.dart

@@ -0,0 +1,91 @@
+/*
+
+
+ -* Time Based Key-Value Store *-
+
+Design a time-based key-value data structure that can store multiple values for the same key at different time stamps and retrieve the key's value at a certain timestamp.
+
+Implement the TimeMap class:
+
+TimeMap() Initializes the object of the data structure.
+void set(String key, String value, int timestamp) Stores the key key with the value value at the given time timestamp.
+String get(String key, int timestamp) Returns a value such that set was called previously, with timestamp_prev <= timestamp. If there are multiple such values, it returns the value associated with the largest timestamp_prev. If there are no values, it returns "".
+
+
+Example 1:
+
+Input
+["TimeMap", "set", "get", "get", "set", "get", "get"]
+[[], ["foo", "bar", 1], ["foo", 1], ["foo", 3], ["foo", "bar2", 4], ["foo", 4], ["foo", 5]]
+Output
+[null, null, "bar", "bar", null, "bar2", "bar2"]
+
+Explanation
+TimeMap timeMap = new TimeMap();
+timeMap.set("foo", "bar", 1);  // store the key "foo" and value "bar" along with timestamp = 1.
+timeMap.get("foo", 1);         // return "bar"
+timeMap.get("foo", 3);         // return "bar", since there is no value corresponding to foo at timestamp 3 and timestamp 2, then the only value is at timestamp 1 is "bar".
+timeMap.set("foo", "bar2", 4); // store the key "foo" and value "bar2" along with timestamp = 4.
+timeMap.get("foo", 4);         // return "bar2"
+timeMap.get("foo", 5);         // return "bar2"
+
+
+Constraints:
+
+1 <= key.length, value.length <= 100
+key and value consist of lowercase English letters and digits.
+1 <= timestamp <= 107
+All the timestamps timestamp of set are strictly increasing.
+At most 2 * 105 calls will be made to set and get.
+
+*/
+
+//Your TimeMap object will be instantiated and called as such:
+
+// class Pair<T1,T2> {
+//     final T1 first;
+//     final T2 second;
+//     Pair(this.first, this.second);
+
+//     bool operator == (final Pair other) {
+//         return first == other.first && second == other.second;
+//     }
+//     int get hashCode => hash(first.hashCode,second.hashCode);
+// }
+
+// class Pair {
+//   late String value;
+//   late int time;
+//   Pair(String _value, int _timestamp) {
+//     time = _timestamp;
+//     value = _value;
+//   }
+// }
+
+// class F {
+//   List<Pair> list = <Pair>[];
+
+//   F(String _value, int _timestamp) {
+//     list.add(Pair(_value, _timestamp));
+//   }
+//   F.from(List<Pair> c) {
+//     list = c;
+//   }
+// }
+
+class TimeMap {
+  Map map = {};
+  TimeMap() {
+    this.map;
+  }
+
+  void set(String key, String value, int timestamp) {}
+
+  String get(String key, int timestamp) {
+    return "";
+  }
+}
+
+// TimeMap obj = TimeMap();
+// obj.set(key,value,timestamp);
+// String param2 = obj.get(key,timestamp);

TimeBasedKeyValueStore/time_based_key_value_store.go

@@ -0,0 +1,50 @@
+package main
+
+import "strconv"
+
+//Runtime: 454 ms, faster than 85.83% of Go online submissions for Time Based Key-Value Store.
+//Memory Usage: 73.3 MB, less than 10.52% of Go online submissions for Time Based Key-Value Store.
+
+type TimeMap struct {
+	timestamps map[string][]int
+	values     map[string]string
+}
+
+// Constructor initializes TimeMap structure
+func Constructor() TimeMap {
+	return TimeMap{
+		timestamps: make(map[string][]int),
+		values:     make(map[string]string),
+	}
+}
+
+// Set value by key and timestamp
+func (tm *TimeMap) Set(key string, value string, timestamp int) {
+	tm.timestamps[key] = append(tm.timestamps[key], timestamp)
+	tm.values[key+strconv.Itoa(timestamp)] = value
+}
+
+// Get value by key and timestamp
+func (tm *TimeMap) Get(key string, timestamp int) string {
+	timestamps, ok := tm.timestamps[key]
+	if !ok || timestamps[0] > timestamp {
+		return ""
+	}
+	if timestamps[len(timestamps)-1] <= timestamp {
+		return tm.values[key+strconv.Itoa(timestamps[len(timestamps)-1])]
+	}
+	left := 0
+	right := len(timestamps) - 1
+	for left < right {
+		mid := left + (right-left)/2
+		if timestamps[mid] == timestamp {
+			return tm.values[key+strconv.Itoa(timestamps[mid])]
+		}
+		if timestamps[mid] < timestamp {
+			left = mid + 1
+		} else {
+			right = mid
+		}
+	}
+	return tm.values[key+strconv.Itoa(timestamps[left-1])]
+}