Create Time_Based_key-value_pairs.py

Python/Time_Based_key-value_pairs.py

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+#Leetcode
+# 981. 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"
+
+class TimeMap:
+
+    def __init__(self):
+        self.map_dict = defaultdict(dict)
+
+
+    def set(self, key: str, value: str, timestamp: int) -> None:
+        self.map_dict[key][timestamp]=value
+
+
+    def get(self, key: str, timestamp: int) -> str:
+        for i in range(timestamp, -1, -1):
+            if i in self.map_dict[key]:
+                return self.map_dict[key][i]
+        return ""
+