706. 设计哈希映射
不使用任何内建的哈希表库设计一个哈希映射（HashMap）。
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 。
示例：
输入： ["MyHashMap", "put", "put", "get", "get", "put", "get", "remove", "get"] [[], [1, 1], [2, 2], [1], [3], [2, 1], [2], [2], [2]] 输出： [null, null, null, 1, -1, null, 1, null, -1] 解释： MyHashMap myHashMap = new MyHashMap(); myHashMap.put(1, 1); // myHashMap 现在为 [[1,1]] myHashMap.put(2, 2); // myHashMap 现在为 [[1,1], [2,2]] myHashMap.get(1); // 返回 1 ，myHashMap 现在为 [[1,1], [2,2]] myHashMap.get(3); // 返回 -1（未找到），myHashMap 现在为 [[1,1], [2,2]] myHashMap.put(2, 1); // myHashMap 现在为 [[1,1], [2,1]]（更新已有的值） myHashMap.get(2); // 返回 1 ，myHashMap 现在为 [[1,1], [2,1]] myHashMap.remove(2); // 删除键为 2 的数据，myHashMap 现在为 [[1,1]] myHashMap.get(2); // 返回 -1（未找到），myHashMap 现在为 [[1,1]]
提示：
0 <= key, value <= 106104 次 put、get 和 remove 方法相似题目
原站题解
python3 解法, 执行用时: 138 ms, 内存消耗: 19.8 MB, 提交时间: 2024-04-20 16:16:57
class MyHashMap:
def __init__(self):
self.buckets = 1009
self.table = [[] for _ in range(self.buckets)]
def hash(self, key):
return key % self.buckets
def put(self, key: int, value: int) -> None:
hashkey = self.hash(key)
for item in self.table[hashkey]:
if item[0] == key:
item[1] = value
return
self.table[hashkey].append([key, value])
def get(self, key: int) -> int:
hashkey = self.hash(key)
for item in self.table[hashkey]:
if item[0] == key:
return item[1]
return -1
def remove(self, key: int) -> None:
hashkey = self.hash(key)
for i, item in enumerate(self.table[hashkey]):
if item[0] == key:
self.table[hashkey].pop(i)
return
# Your MyHashMap object will be instantiated and called as such:
# obj = MyHashMap()
# obj.put(key,value)
# param_2 = obj.get(key)
# obj.remove(key)
python3 解法, 执行用时: 330 ms, 内存消耗: 34.2 MB, 提交时间: 2024-04-20 16:16:24
class MyHashMap:
def __init__(self):
self.map = [[-1] * 1000 for _ in range(1001)]
def put(self, key: int, value: int) -> None:
row, col = key // 1000, key % 1000
self.map[row][col] = value
def get(self, key: int) -> int:
row, col = key // 1000, key % 1000
return self.map[row][col]
def remove(self, key: int) -> None:
row, col = key // 1000, key % 1000
self.map[row][col] = -1
# Your MyHashMap object will be instantiated and called as such:
# obj = MyHashMap()
# obj.put(key,value)
# param_2 = obj.get(key)
# obj.remove(key)
python3 解法, 执行用时: 252 ms, 内存消耗: 41.2 MB, 提交时间: 2024-04-20 16:15:05
class MyHashMap:
def __init__(self):
self.map = [-1] * 1000001
def put(self, key: int, value: int) -> None:
self.map[key] = value
def get(self, key: int) -> int:
return self.map[key]
def remove(self, key: int) -> None:
self.map[key] = -1
# Your MyHashMap object will be instantiated and called as such:
# obj = MyHashMap()
# obj.put(key,value)
# param_2 = obj.get(key)
# obj.remove(key)
javascript 解法, 执行用时: 176 ms, 内存消耗: 59.7 MB, 提交时间: 2024-04-20 16:13:22
var MyHashMap = function() {
this.BASE = 769;
this.data = new Array(this.BASE).fill(0).map(() => new Array());
};
MyHashMap.prototype.put = function(key, value) {
const h = this.hash(key);
for (const it of this.data[h]) {
if (it[0] === key) {
it[1] = value;
return;
}
}
this.data[h].push([key, value]);
};
MyHashMap.prototype.get = function(key) {
const h = this.hash(key);
for (const it of this.data[h]) {
if (it[0] === key) {
return it[1];
}
}
return -1;
};
MyHashMap.prototype.remove = function(key) {
const h = this.hash(key);
for (const it of this.data[h]) {
if (it[0] === key) {
const idx = this.data[h].indexOf(it);
this.data[h].splice(idx, 1);
return;
}
}
};
MyHashMap.prototype.hash = function(key) {
return key % this.BASE;
}
/**
* Your MyHashMap object will be instantiated and called as such:
* var obj = new MyHashMap()
* obj.put(key,value)
* var param_2 = obj.get(key)
* obj.remove(key)
*/
java 解法, 执行用时: 17 ms, 内存消耗: 46.7 MB, 提交时间: 2024-04-20 16:13:00
class MyHashMap {
private class Pair {
private int key;
private int value;
public Pair(int key, int value) {
this.key = key;
this.value = value;
}
public int getKey() {
return key;
}
public int getValue() {
return value;
}
public void setValue(int value) {
this.value = value;
}
}
private static final int BASE = 769;
private LinkedList[] data;
/** Initialize your data structure here. */
public MyHashMap() {
data = new LinkedList[BASE];
for (int i = 0; i < BASE; ++i) {
data[i] = new LinkedList<Pair>();
}
}
/** value will always be non-negative. */
public void put(int key, int value) {
int h = hash(key);
Iterator<Pair> iterator = data[h].iterator();
while (iterator.hasNext()) {
Pair pair = iterator.next();
if (pair.getKey() == key) {
pair.setValue(value);
return;
}
}
data[h].offerLast(new Pair(key, value));
}
/** Returns the value to which the specified key is mapped, or -1 if this map contains no mapping for the key */
public int get(int key) {
int h = hash(key);
Iterator<Pair> iterator = data[h].iterator();
while (iterator.hasNext()) {
Pair pair = iterator.next();
if (pair.getKey() == key) {
return pair.value;
}
}
return -1;
}
/** Removes the mapping of the specified value key if this map contains a mapping for the key */
public void remove(int key) {
int h = hash(key);
Iterator<Pair> iterator = data[h].iterator();
while (iterator.hasNext()) {
Pair pair = iterator.next();
if (pair.key == key) {
data[h].remove(pair);
return;
}
}
}
private static int hash(int key) {
return key % BASE;
}
}
/**
* Your MyHashMap object will be instantiated and called as such:
* MyHashMap obj = new MyHashMap();
* obj.put(key,value);
* int param_2 = obj.get(key);
* obj.remove(key);
*/
cpp 解法, 执行用时: 106 ms, 内存消耗: 55.2 MB, 提交时间: 2024-04-20 16:12:42
class MyHashMap {
private:
vector<list<pair<int, int>>> data;
static const int base = 769;
static int hash(int key) {
return key % base;
}
public:
/** Initialize your data structure here. */
MyHashMap(): data(base) {}
/** value will always be non-negative. */
void put(int key, int value) {
int h = hash(key);
for (auto it = data[h].begin(); it != data[h].end(); it++) {
if ((*it).first == key) {
(*it).second = value;
return;
}
}
data[h].push_back(make_pair(key, value));
}
/** Returns the value to which the specified key is mapped, or -1 if this map contains no mapping for the key */
int get(int key) {
int h = hash(key);
for (auto it = data[h].begin(); it != data[h].end(); it++) {
if ((*it).first == key) {
return (*it).second;
}
}
return -1;
}
/** Removes the mapping of the specified value key if this map contains a mapping for the key */
void remove(int key) {
int h = hash(key);
for (auto it = data[h].begin(); it != data[h].end(); it++) {
if ((*it).first == key) {
data[h].erase(it);
return;
}
}
}
};
/**
* Your MyHashMap object will be instantiated and called as such:
* MyHashMap* obj = new MyHashMap();
* obj->put(key,value);
* int param_2 = obj->get(key);
* obj->remove(key);
*/
golang 解法, 执行用时: 112 ms, 内存消耗: 8.3 MB, 提交时间: 2021-08-05 17:24:12
const base = 769
type entry struct {
key, value int
}
type MyHashMap struct {
data []list.List
}
/** Initialize your data structure here. */
func Constructor() MyHashMap {
return MyHashMap{make([]list.List, base)}
}
func (this *MyHashMap) hash(key int) int {
return key % base
}
/** value will always be non-negative. */
func (this *MyHashMap) Put(key int, value int) {
h := this.hash(key)
for e := this.data[h].Front(); e != nil; e = e.Next() {
if et := e.Value.(entry); et.key == key {
e.Value = entry{key, value}
return
}
}
this.data[h].PushBack(entry{key, value})
}
/** Returns the value to which the specified key is mapped, or -1 if this map contains no mapping for the key */
func (this *MyHashMap) Get(key int) int {
h := this.hash(key)
for e := this.data[h].Front(); e != nil; e = e.Next() {
if et := e.Value.(entry); et.key == key {
return et.value
}
}
return -1
}
/** Removes the mapping of the specified value key if this map contains a mapping for the key */
func (this *MyHashMap) Remove(key int) {
h := this.hash(key)
for e := this.data[h].Front(); e != nil; e = e.Next() {
if et := e.Value.(entry); et.key == key {
this.data[h].Remove(e)
return
}
}
}
/**
* Your MyHashMap object will be instantiated and called as such:
* obj := Constructor();
* obj.Put(key,value);
* param_2 := obj.Get(key);
* obj.Remove(key);
*/