{ "data": { "question": { "questionId": "1023", "questionFrontendId": "981", "boundTopicId": null, "title": "Time Based Key-Value Store", "titleSlug": "time-based-key-value-store", "content": "
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.
\n\nImplement 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 ""
.\n
Example 1:
\n\n\nInput\n["TimeMap", "set", "get", "get", "set", "get", "get"]\n[[], ["foo", "bar", 1], ["foo", 1], ["foo", 3], ["foo", "bar2", 4], ["foo", 4], ["foo", 5]]\nOutput\n[null, null, "bar", "bar", null, "bar2", "bar2"]\n\nExplanation\nTimeMap timeMap = new TimeMap();\ntimeMap.set("foo", "bar", 1); // store the key "foo" and value "bar" along with timestamp = 1.\ntimeMap.get("foo", 1); // return "bar"\ntimeMap.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".\ntimeMap.set("foo", "bar2", 4); // store the key "foo" and value "bar2" along with timestamp = 4.\ntimeMap.get("foo", 4); // return "bar2"\ntimeMap.get("foo", 5); // return "bar2"\n\n\n
\n
Constraints:
\n\n1 <= key.length, value.length <= 100
key
and value
consist of lowercase English letters and digits.1 <= timestamp <= 107
timestamp
of set
are strictly increasing.2 * 105
calls will be made to set
and get
.Compiled with clang 11
using the latest C++ 17 standard.
Your code is compiled with level two optimization (-O2
). AddressSanitizer is also enabled to help detect out-of-bounds and use-after-free bugs.
Most standard library headers are already included automatically for your convenience.
\"], \"java\": [\"Java\", \" OpenJDK 17
. Java 8 features such as lambda expressions and stream API can be used.
Most standard library headers are already included automatically for your convenience.
\\r\\nIncludes Pair
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Python 2.7.12
.
Most libraries are already imported automatically for your convenience, such as array, bisect, collections. If you need more libraries, you can import it yourself.
\\r\\n\\r\\nFor Map/TreeMap data structure, you may use sortedcontainers library.
\\r\\n\\r\\nNote that Python 2.7 will not be maintained past 2020. For the latest Python, please choose Python3 instead.
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Your code is compiled with level one optimization (-O1
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Most standard library headers are already included automatically for your convenience.
\\r\\n\\r\\nFor hash table operations, you may use uthash. \\\"uthash.h\\\" is included by default. Below are some examples:
\\r\\n\\r\\n1. Adding an item to a hash.\\r\\n
\\r\\nstruct hash_entry {\\r\\n int id; /* we'll use this field as the key */\\r\\n char name[10];\\r\\n UT_hash_handle hh; /* makes this structure hashable */\\r\\n};\\r\\n\\r\\nstruct hash_entry *users = NULL;\\r\\n\\r\\nvoid add_user(struct hash_entry *s) {\\r\\n HASH_ADD_INT(users, id, s);\\r\\n}\\r\\n\\r\\n\\r\\n\\r\\n
2. Looking up an item in a hash:\\r\\n
\\r\\nstruct hash_entry *find_user(int user_id) {\\r\\n struct hash_entry *s;\\r\\n HASH_FIND_INT(users, &user_id, s);\\r\\n return s;\\r\\n}\\r\\n\\r\\n\\r\\n\\r\\n
3. Deleting an item in a hash:\\r\\n
\\r\\nvoid delete_user(struct hash_entry *user) {\\r\\n HASH_DEL(users, user); \\r\\n}\\r\\n\\r\\n\"], \"csharp\": [\"C#\", \"\\r\\n\\r\\n
Your code is compiled with debug flag enabled (/debug
).
Node.js 16.13.2
.
Your code is run with --harmony
flag, enabling new ES6 features.
lodash.js library is included by default.
\\r\\n\\r\\nFor Priority Queue / Queue data structures, you may use datastructures-js/priority-queue and datastructures-js/queue.
\"], \"ruby\": [\"Ruby\", \"Ruby 3.1
Some common data structure implementations are provided in the Algorithms module: https://www.rubydoc.info/github/kanwei/algorithms/Algorithms
\"], \"swift\": [\"Swift\", \"Swift 5.5.2
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Go 1.17.6
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Support https://godoc.org/github.com/emirpasic/gods library.
\"], \"python3\": [\"Python3\", \"Python 3.10
.
Most libraries are already imported automatically for your convenience, such as array, bisect, collections. If you need more libraries, you can import it yourself.
\\r\\n\\r\\nFor Map/TreeMap data structure, you may use sortedcontainers library.
\"], \"scala\": [\"Scala\", \"Scala 2.13.7
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Kotlin 1.3.10
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Rust 1.58.1
Supports rand v0.6\\u00a0from crates.io
\"], \"php\": [\"PHP\", \"PHP 8.1
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With bcmath module
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Your code is run with --harmony
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