{ "data": { "question": { "questionId": "817", "questionFrontendId": "706", "categoryTitle": "Algorithms", "boundTopicId": 1694, "title": "Design HashMap", "titleSlug": "design-hashmap", "content": "
Design a HashMap without using any built-in hash table libraries.
\n\nImplement the MyHashMap
class:
MyHashMap()
initializes the object with an empty map.void put(int key, int value)
inserts a (key, value)
pair into the HashMap. If the key
already exists in the map, update the corresponding value
.int get(int key)
returns the value
to which the specified key
is mapped, or -1
if this map contains no mapping for the key
.void remove(key)
removes the key
and its corresponding value
if the map contains the mapping for the key
.\n
Example 1:
\n\n\nInput\n["MyHashMap", "put", "put", "get", "get", "put", "get", "remove", "get"]\n[[], [1, 1], [2, 2], [1], [3], [2, 1], [2], [2], [2]]\nOutput\n[null, null, null, 1, -1, null, 1, null, -1]\n\nExplanation\nMyHashMap myHashMap = new MyHashMap();\nmyHashMap.put(1, 1); // The map is now [[1,1]]\nmyHashMap.put(2, 2); // The map is now [[1,1], [2,2]]\nmyHashMap.get(1); // return 1, The map is now [[1,1], [2,2]]\nmyHashMap.get(3); // return -1 (i.e., not found), The map is now [[1,1], [2,2]]\nmyHashMap.put(2, 1); // The map is now [[1,1], [2,1]] (i.e., update the existing value)\nmyHashMap.get(2); // return 1, The map is now [[1,1], [2,1]]\nmyHashMap.remove(2); // remove the mapping for 2, The map is now [[1,1]]\nmyHashMap.get(2); // return -1 (i.e., not found), The map is now [[1,1]]\n\n\n
\n
Constraints:
\n\n0 <= key, value <= 106
104
calls will be made to put
, get
, and remove
.不使用任何内建的哈希表库设计一个哈希映射(HashMap)。
\n\n实现 MyHashMap
类:
MyHashMap()
用空映射初始化对象void put(int key, int value)
向 HashMap 插入一个键值对 (key, value)
。如果 key
已经存在于映射中,则更新其对应的值 value
。int get(int key)
返回特定的 key
所映射的 value
;如果映射中不包含 key
的映射,返回 -1
。void remove(key)
如果映射中存在 key
的映射,则移除 key
和它所对应的 value
。\n\n
示例:
\n\n\n输入:\n[\"MyHashMap\", \"put\", \"put\", \"get\", \"get\", \"put\", \"get\", \"remove\", \"get\"]\n[[], [1, 1], [2, 2], [1], [3], [2, 1], [2], [2], [2]]\n输出:\n[null, null, null, 1, -1, null, 1, null, -1]\n\n解释:\nMyHashMap myHashMap = new MyHashMap();\nmyHashMap.put(1, 1); // myHashMap 现在为 [[1,1]]\nmyHashMap.put(2, 2); // myHashMap 现在为 [[1,1], [2,2]]\nmyHashMap.get(1); // 返回 1 ,myHashMap 现在为 [[1,1], [2,2]]\nmyHashMap.get(3); // 返回 -1(未找到),myHashMap 现在为 [[1,1], [2,2]]\nmyHashMap.put(2, 1); // myHashMap 现在为 [[1,1], [2,1]](更新已有的值)\nmyHashMap.get(2); // 返回 1 ,myHashMap 现在为 [[1,1], [2,1]]\nmyHashMap.remove(2); // 删除键为 2 的数据,myHashMap 现在为 [[1,1]]\nmyHashMap.get(2); // 返回 -1(未找到),myHashMap 现在为 [[1,1]]\n\n\n
\n\n
提示:
\n\n0 <= key, value <= 106
104
次 put
、get
和 remove
方法\\u7248\\u672c\\uff1a \\u7f16\\u8bd1\\u65f6\\uff0c\\u5c06\\u4f1a\\u91c7\\u7528 \\u4e3a\\u4e86\\u4f7f\\u7528\\u65b9\\u4fbf\\uff0c\\u5927\\u90e8\\u5206\\u6807\\u51c6\\u5e93\\u7684\\u5934\\u6587\\u4ef6\\u5df2\\u7ecf\\u88ab\\u81ea\\u52a8\\u5bfc\\u5165\\u3002<\\/p>\"],\"java\":[\"Java\",\" \\u7248\\u672c\\uff1a \\u4e3a\\u4e86\\u65b9\\u4fbf\\u8d77\\u89c1\\uff0c\\u5927\\u90e8\\u5206\\u6807\\u51c6\\u5e93\\u7684\\u5934\\u6587\\u4ef6\\u5df2\\u88ab\\u5bfc\\u5165\\u3002<\\/p>\\r\\n\\r\\n \\u5305\\u542b Pair \\u7c7b: https:\\/\\/docs.oracle.com\\/javase\\/8\\/javafx\\/api\\/javafx\\/util\\/Pair.html <\\/p>\"],\"python\":[\"Python\",\" \\u7248\\u672c\\uff1a \\u4e3a\\u4e86\\u65b9\\u4fbf\\u8d77\\u89c1\\uff0c\\u5927\\u90e8\\u5206\\u5e38\\u7528\\u5e93\\u5df2\\u7ecf\\u88ab\\u81ea\\u52a8 \\u5bfc\\u5165\\uff0c\\u5982\\uff1aarray<\\/a>, bisect<\\/a>, collections<\\/a>\\u3002\\u5982\\u679c\\u60a8\\u9700\\u8981\\u4f7f\\u7528\\u5176\\u4ed6\\u5e93\\u51fd\\u6570\\uff0c\\u8bf7\\u81ea\\u884c\\u5bfc\\u5165\\u3002<\\/p>\\r\\n\\r\\n \\u6ce8\\u610f Python 2.7 \\u5c06\\u57282020\\u5e74\\u540e\\u4e0d\\u518d\\u7ef4\\u62a4<\\/a>\\u3002 \\u5982\\u60f3\\u4f7f\\u7528\\u6700\\u65b0\\u7248\\u7684Python\\uff0c\\u8bf7\\u9009\\u62e9Python 3\\u3002<\\/p>\"],\"c\":[\"C\",\" \\u7248\\u672c\\uff1a \\u7f16\\u8bd1\\u65f6\\uff0c\\u5c06\\u4f1a\\u91c7\\u7528 \\u4e3a\\u4e86\\u4f7f\\u7528\\u65b9\\u4fbf\\uff0c\\u5927\\u90e8\\u5206\\u6807\\u51c6\\u5e93\\u7684\\u5934\\u6587\\u4ef6\\u5df2\\u7ecf\\u88ab\\u81ea\\u52a8\\u5bfc\\u5165\\u3002<\\/p>\\r\\n\\r\\n \\u5982\\u60f3\\u4f7f\\u7528\\u54c8\\u5e0c\\u8868\\u8fd0\\u7b97, \\u60a8\\u53ef\\u4ee5\\u4f7f\\u7528 uthash<\\/a>\\u3002 \\\"uthash.h\\\"\\u5df2\\u7ecf\\u9ed8\\u8ba4\\u88ab\\u5bfc\\u5165\\u3002\\u8bf7\\u770b\\u5982\\u4e0b\\u793a\\u4f8b:<\\/p>\\r\\n\\r\\n 1. 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\\u5e93\\u5df2\\u7ecf\\u9ed8\\u8ba4\\u88ab\\u5305\\u542b\\u3002<\\/p>\\r\\n\\r\\n \\u5982\\u9700\\u4f7f\\u7528\\u961f\\u5217\\/\\u4f18\\u5148\\u961f\\u5217\\uff0c\\u60a8\\u53ef\\u4f7f\\u7528 datastructures-js\\/priority-queue@5.3.0<\\/a> \\u548c datastructures-js\\/queue@4.2.1<\\/a>\\u3002<\\/p>\"],\"racket\":[\"Racket\",\"clang 11<\\/code> \\u91c7\\u7528\\u6700\\u65b0C++ 20\\u6807\\u51c6\\u3002<\\/p>\\r\\n\\r\\n
-O2<\\/code>\\u7ea7\\u4f18\\u5316\\u3002AddressSanitizer<\\/a> \\u4e5f\\u88ab\\u5f00\\u542f\\u6765\\u68c0\\u6d4b
out-of-bounds<\\/code>\\u548c
use-after-free<\\/code>\\u9519\\u8bef\\u3002<\\/p>\\r\\n\\r\\n
OpenJDK 17<\\/code>\\u3002\\u53ef\\u4ee5\\u4f7f\\u7528Java 8\\u7684\\u7279\\u6027\\u4f8b\\u5982\\uff0clambda expressions \\u548c stream API\\u3002<\\/p>\\r\\n\\r\\n
Python 2.7.12<\\/code><\\/p>\\r\\n\\r\\n
GCC 8.2<\\/code>\\uff0c\\u91c7\\u7528GNU11\\u6807\\u51c6\\u3002<\\/p>\\r\\n\\r\\n
-O1<\\/code>\\u7ea7\\u4f18\\u5316\\u3002 AddressSanitizer<\\/a>\\u4e5f\\u88ab\\u5f00\\u542f\\u6765\\u68c0\\u6d4b
out-of-bounds<\\/code>\\u548c
use-after-free<\\/code>\\u9519\\u8bef\\u3002<\\/p>\\r\\n\\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<\\/pre>\\r\\n<\\/p>\\r\\n\\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<\\/pre>\\r\\n<\\/p>\\r\\n\\r\\n
\\r\\nvoid delete_user(struct hash_entry *user) {\\r\\n HASH_DEL(users, user); \\r\\n}\\r\\n<\\/pre>\\r\\n<\\/p>\"],\"csharp\":[\"C#\",\"
Node.js 16.13.2<\\/code><\\/p>\\r\\n\\r\\n
--harmony<\\/code> \\u6807\\u8bb0\\u6765\\u5f00\\u542f \\u65b0\\u7248ES6\\u7279\\u6027<\\/a>\\u3002<\\/p>\\r\\n\\r\\n
Ruby 3.1<\\/code>\\u6267\\u884c<\\/p>\\r\\n\\r\\n
Swift 5.5.2<\\/code><\\/p>\\r\\n\\r\\n
Go 1.21<\\/code><\\/p>\\r\\n\\r\\n
Python 3.10<\\/code><\\/p>\\r\\n\\r\\n
Scala 2.13<\\/code><\\/p>\"],\"kotlin\":[\"Kotlin\",\"
Kotlin 1.9.0<\\/code><\\/p>\\r\\n\\r\\n
rust 1.58.1<\\/code><\\/p>\\r\\n\\r\\n
PHP 8.1<\\/code>.<\\/p>\\r\\n\\r\\n