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Nov 17, 2023
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feat: add solutions to lc problem: No.0288 #1976

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120 changes: 77 additions & 43 deletions solution/0200-0299/0288.Unique Word Abbreviation/README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -67,7 +67,15 @@ validWordAbbr.isUnique("cake"); // 返回 true，因为 "cake" 已经存在于

<!-- 这里可写通用的实现逻辑 -->

哈希表实现，其中 key 存放单词缩写，value 存放单词缩写所对应的所有单词的集合。
**方法一：哈希表**

根据题目描述，我们定义一个函数 $abbr(s)$，它的功能是计算单词 $s$ 的缩写。如果单词 $s$ 的长度小于 $3$，那么它的缩写就是它本身；否则，它的缩写是它的首字母 + (它的长度 - 2) + 它的尾字母。

接下来，我们定义一个哈希表 $d$，它的键是单词的缩写，值是一个集合，集合中的元素是所有缩写为该键的单词。我们遍历给定的单词字典，对于字典中的每个单词 $s$，我们求出它的缩写 $abbr(s)$，并将 $s$ 添加到 $d[abbr(s)]$ 中。

在判断单词 $word$ 是否满足题目要求时，我们求出它的缩写 $abbr(word)$，如果 $abbr(word)$ 不在哈希表 $d$ 中，那么 $word$ 满足题目要求；否则，我们判断 $d[abbr(word)]$ 中是否只有一个元素，如果 $d[abbr(word)]$ 中只有一个元素且该元素就是 $word$，那么 $word$ 满足题目要求。

时间复杂度方面，初始化哈希表的时间复杂度是 $O(n)$，其中 $n$ 是单词字典的长度；判断单词是否满足题目要求的时间复杂度是 $O(1)$。空间复杂度方面，哈希表的空间复杂度是 $O(n)$。

<!-- tabs:start -->

Expand All @@ -78,18 +86,16 @@ validWordAbbr.isUnique("cake"); // 返回 true，因为 "cake" 已经存在于
```python
class ValidWordAbbr:
def __init__(self, dictionary: List[str]):
self.words = defaultdict(set)
for word in dictionary:
abbr = self.word_abbr(word)
self.words[abbr].add(word)
self.d = defaultdict(set)
for s in dictionary:
self.d[self.abbr(s)].add(s)

def isUnique(self, word: str) -> bool:
abbr = self.word_abbr(word)
words = self.words[abbr]
return not words or (len(words) == 1 and word in words)
s = self.abbr(word)
return s not in self.d or all(word == t for t in self.d[s])

def word_abbr(self, s):
return s if len(s) < 3 else f'{s[0]}{len(s) - 2}{s[-1]}'
def abbr(self, s: str) -> str:
return s if len(s) < 3 else s[0] + str(len(s) - 2) + s[-1]


# Your ValidWordAbbr object will be instantiated and called as such:
Expand All @@ -103,25 +109,22 @@ class ValidWordAbbr:

```java
class ValidWordAbbr {
private Map<String, Set<String>> words;
private Map<String, Set<String>> d = new HashMap<>();

public ValidWordAbbr(String[] dictionary) {
words = new HashMap<>();
for (String word : dictionary) {
String abbr = abbr(word);
words.computeIfAbsent(abbr, k -> new HashSet<>()).add(word);
for (var s : dictionary) {
d.computeIfAbsent(abbr(s), k -> new HashSet<>()).add(s);
}
}

public boolean isUnique(String word) {
String abbr = abbr(word);
Set<String> vals = words.get(abbr);
return vals == null || (vals.size() == 1 && vals.contains(word));
var ws = d.get(abbr(word));
return ws == null || (ws.size() == 1 && ws.contains(word));
}

private String abbr(String s) {
int n = s.length();
return n < 3 ? s : s.charAt(0) + Integer.toString(n - 2) + s.charAt(n - 1);
return n < 3 ? s : s.substring(0, 1) + (n - 2) + s.substring(n - 1);
}
}

Expand All @@ -137,23 +140,21 @@ class ValidWordAbbr {
```cpp
class ValidWordAbbr {
public:
unordered_map<string, unordered_set<string>> words;

ValidWordAbbr(vector<string>& dictionary) {
for (auto word : dictionary) {
auto abbr = wordAbbr(word);
words[abbr].insert(word);
for (auto& s : dictionary) {
d[abbr(s)].insert(s);
}
}

bool isUnique(string word) {
auto abbr = wordAbbr(word);
if (!words.count(abbr)) return true;
auto vals = words[abbr];
return vals.size() == 1 && vals.count(word);
string s = abbr(word);
return !d.count(s) || (d[s].size() == 1 && d[s].count(word));
}

string wordAbbr(string s) {
private:
unordered_map<string, unordered_set<string>> d;

string abbr(string& s) {
int n = s.size();
return n < 3 ? s : s.substr(0, 1) + to_string(n - 2) + s.substr(n - 1, 1);
}
Expand All @@ -170,33 +171,32 @@ public:

```go
type ValidWordAbbr struct {
words map[string]map[string]bool
d map[string]map[string]bool
}

func Constructor(dictionary []string) ValidWordAbbr {
words := make(map[string]map[string]bool)
for _, word := range dictionary {
abbr := wordAbbr(word)
if words[abbr] == nil {
words[abbr] = make(map[string]bool)
d := make(map[string]map[string]bool)
for _, s := range dictionary {
abbr := abbr(s)
if _, ok := d[abbr]; !ok {
d[abbr] = make(map[string]bool)
}
words[abbr][word] = true
d[abbr][s] = true
}
return ValidWordAbbr{words}
return ValidWordAbbr{d}
}

func (this *ValidWordAbbr) IsUnique(word string) bool {
abbr := wordAbbr(word)
words := this.words[abbr]
return words == nil || (len(words) == 1 && words[word])
ws := this.d[abbr(word)]
return ws == nil || (len(ws) == 1 && ws[word])
}

func wordAbbr(s string) string {
func abbr(s string) string {
n := len(s)
if n <= 2 {
if n < 3 {
return s
}
return s[0:1] + strconv.Itoa(n-2) + s[n-1:]
return fmt.Sprintf("%c%d%c", s[0], n-2, s[n-1])
}

/**
Expand All @@ -206,6 +206,40 @@ func wordAbbr(s string) string {
*/
```

### **TypeScript**

```ts
class ValidWordAbbr {
private d: Map<string, Set<string>> = new Map();

constructor(dictionary: string[]) {
for (const s of dictionary) {
const abbr = this.abbr(s);
if (!this.d.has(abbr)) {
this.d.set(abbr, new Set());
}
this.d.get(abbr)!.add(s);
}
}

isUnique(word: string): boolean {
const ws = this.d.get(this.abbr(word));
return ws === undefined || (ws.size === 1 && ws.has(word));
}

abbr(s: string): string {
const n = s.length;
return n < 3 ? s : s[0] + (n - 2) + s[n - 1];
}
}

/**
* Your ValidWordAbbr object will be instantiated and called as such:
* var obj = new ValidWordAbbr(dictionary)
* var param_1 = obj.isUnique(word)
*/
```

### **...**

```
Expand Down
120 changes: 78 additions & 42 deletions solution/0200-0299/0288.Unique Word Abbreviation/README_EN.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -59,25 +59,33 @@ validWordAbbr.isUnique(&quot;cake&quot;); // return true, because &quot;cake&quo

## Solutions

**Solution 1: Hash Table**

According to the problem description, we define a function $abbr(s)$, which calculates the abbreviation of the word $s$. If the length of the word $s$ is less than $3$, then its abbreviation is itself; otherwise, its abbreviation is its first letter + (its length - 2) + its last letter.

Next, we define a hash table $d$, where the key is the abbreviation of the word, and the value is a set, the elements of which are all words abbreviated as that key. We traverse the given word dictionary, and for each word $s$ in the dictionary, we calculate its abbreviation $abbr(s)$, and add $s$ to $d[abbr(s)]$.

When judging whether the word $word$ meets the requirements of the problem, we calculate its abbreviation $abbr(word)$. If $abbr(word)$ is not in the hash table $d$, then $word$ meets the requirements of the problem; otherwise, we judge whether there is only one element in $d[abbr(word)]$. If there is only one element in $d[abbr(word)]$ and that element is $word$, then $word$ meets the requirements of the problem.

In terms of time complexity, the time complexity of initializing the hash table is $O(n)$, where $n$ is the length of the word dictionary; the time complexity of judging whether a word meets the requirements of the problem is $O(1)$. In terms of space complexity, the space complexity of the hash table is $O(n)$.

<!-- tabs:start -->

### **Python3**

```python
class ValidWordAbbr:
def __init__(self, dictionary: List[str]):
self.words = defaultdict(set)
for word in dictionary:
abbr = self.word_abbr(word)
self.words[abbr].add(word)
self.d = defaultdict(set)
for s in dictionary:
self.d[self.abbr(s)].add(s)

def isUnique(self, word: str) -> bool:
abbr = self.word_abbr(word)
words = self.words[abbr]
return not words or (len(words) == 1 and word in words)
s = self.abbr(word)
return s not in self.d or all(word == t for t in self.d[s])

def word_abbr(self, s):
return s if len(s) < 3 else f'{s[0]}{len(s) - 2}{s[-1]}'
def abbr(self, s: str) -> str:
return s if len(s) < 3 else s[0] + str(len(s) - 2) + s[-1]


# Your ValidWordAbbr object will be instantiated and called as such:
Expand All @@ -89,25 +97,22 @@ class ValidWordAbbr:

```java
class ValidWordAbbr {
private Map<String, Set<String>> words;
private Map<String, Set<String>> d = new HashMap<>();

public ValidWordAbbr(String[] dictionary) {
words = new HashMap<>();
for (String word : dictionary) {
String abbr = abbr(word);
words.computeIfAbsent(abbr, k -> new HashSet<>()).add(word);
for (var s : dictionary) {
d.computeIfAbsent(abbr(s), k -> new HashSet<>()).add(s);
}
}

public boolean isUnique(String word) {
String abbr = abbr(word);
Set<String> vals = words.get(abbr);
return vals == null || (vals.size() == 1 && vals.contains(word));
var ws = d.get(abbr(word));
return ws == null || (ws.size() == 1 && ws.contains(word));
}

private String abbr(String s) {
int n = s.length();
return n < 3 ? s : s.charAt(0) + Integer.toString(n - 2) + s.charAt(n - 1);
return n < 3 ? s : s.substring(0, 1) + (n - 2) + s.substring(n - 1);
}
}

Expand All @@ -123,23 +128,21 @@ class ValidWordAbbr {
```cpp
class ValidWordAbbr {
public:
unordered_map<string, unordered_set<string>> words;

ValidWordAbbr(vector<string>& dictionary) {
for (auto word : dictionary) {
auto abbr = wordAbbr(word);
words[abbr].insert(word);
for (auto& s : dictionary) {
d[abbr(s)].insert(s);
}
}

bool isUnique(string word) {
auto abbr = wordAbbr(word);
if (!words.count(abbr)) return true;
auto vals = words[abbr];
return vals.size() == 1 && vals.count(word);
string s = abbr(word);
return !d.count(s) || (d[s].size() == 1 && d[s].count(word));
}

string wordAbbr(string s) {
private:
unordered_map<string, unordered_set<string>> d;

string abbr(string& s) {
int n = s.size();
return n < 3 ? s : s.substr(0, 1) + to_string(n - 2) + s.substr(n - 1, 1);
}
Expand All @@ -156,33 +159,32 @@ public:

```go
type ValidWordAbbr struct {
words map[string]map[string]bool
d map[string]map[string]bool
}

func Constructor(dictionary []string) ValidWordAbbr {
words := make(map[string]map[string]bool)
for _, word := range dictionary {
abbr := wordAbbr(word)
if words[abbr] == nil {
words[abbr] = make(map[string]bool)
d := make(map[string]map[string]bool)
for _, s := range dictionary {
abbr := abbr(s)
if _, ok := d[abbr]; !ok {
d[abbr] = make(map[string]bool)
}
words[abbr][word] = true
d[abbr][s] = true
}
return ValidWordAbbr{words}
return ValidWordAbbr{d}
}

func (this *ValidWordAbbr) IsUnique(word string) bool {
abbr := wordAbbr(word)
words := this.words[abbr]
return words == nil || (len(words) == 1 && words[word])
ws := this.d[abbr(word)]
return ws == nil || (len(ws) == 1 && ws[word])
}

func wordAbbr(s string) string {
func abbr(s string) string {
n := len(s)
if n <= 2 {
if n < 3 {
return s
}
return s[0:1] + strconv.Itoa(n-2) + s[n-1:]
return fmt.Sprintf("%c%d%c", s[0], n-2, s[n-1])
}

/**
Expand All @@ -192,6 +194,40 @@ func wordAbbr(s string) string {
*/
```

### **TypeScript**

```ts
class ValidWordAbbr {
private d: Map<string, Set<string>> = new Map();

constructor(dictionary: string[]) {
for (const s of dictionary) {
const abbr = this.abbr(s);
if (!this.d.has(abbr)) {
this.d.set(abbr, new Set());
}
this.d.get(abbr)!.add(s);
}
}

isUnique(word: string): boolean {
const ws = this.d.get(this.abbr(word));
return ws === undefined || (ws.size === 1 && ws.has(word));
}

abbr(s: string): string {
const n = s.length;
return n < 3 ? s : s[0] + (n - 2) + s[n - 1];
}
}

/**
* Your ValidWordAbbr object will be instantiated and called as such:
* var obj = new ValidWordAbbr(dictionary)
* var param_1 = obj.isUnique(word)
*/
```

### **...**

```
Expand Down
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