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feat: add solutions to lc problem: No.0720
No.0720.Longest Word in Dictionary
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‎solution/0700-0799/0720.Longest Word in Dictionary/README.md

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Original file line numberDiff line numberDiff line change
@@ -42,6 +42,12 @@
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<!-- 这里可写通用的实现逻辑 -->
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**方法一：哈希表**
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用哈希表存放所有单词。遍历这些单词，找出**长度最长且字典序最小**的单词。
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**方法二：排序**
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优先返回符合条件、**长度最长且字典序最小**的单词，那么可以进行依照该规则，先对 `words` 进行排序，免去多个结果之间的比较。
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<!-- tabs:start -->
@@ -51,15 +57,55 @@
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<!-- 这里可写当前语言的特殊实现逻辑 -->
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```python
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class Solution:
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def longestWord(self, words: List[str]) -> str:
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cnt, ans = 0, ''
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s = set(words)
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for w in s:
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n = len(w)
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if all(w[:i] in s for i in range(1, n)):
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if cnt < n:
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cnt, ans = n, w
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elif cnt == n and w < ans:
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ans = w
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return ans
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```
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### **Java**
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<!-- 这里可写当前语言的特殊实现逻辑 -->
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```java
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class Solution {
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private Set<String> s;
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public String longestWord(String[] words) {
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s = new HashSet<>(Arrays.asList(words));
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int cnt = 0;
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String ans = "";
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for (String w : s) {
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int n = w.length();
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if (check(w)) {
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if (cnt < n) {
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cnt = n;
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ans = w;
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} else if (cnt == n && w.compareTo(ans) < 0) {
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ans = w;
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}
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}
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}
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return ans;
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}
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private boolean check(String word) {
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for (int i = 1, n = word.length(); i < n; ++i) {
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if (!s.contains(word.substring(0, i))) {
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return false;
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}
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}
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return true;
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}
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}
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```
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### **TypeScript**
@@ -113,6 +159,72 @@ impl Solution {
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}
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```
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### **C++**
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```cpp
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class Solution {
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public:
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string longestWord(vector<string>& words) {
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unordered_set<string> s(words.begin(), words.end());
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int cnt = 0;
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string ans = "";
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for (auto w : s)
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{
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int n = w.size();
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if (check(w, s))
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{
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if (cnt < n)
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{
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cnt = n;
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ans = w;
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}
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else if (cnt == n && w < ans) ans = w;
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}
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}
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return ans;
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}
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bool check(string& word, unordered_set<string>& s) {
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for (int i = 1, n = word.size(); i < n; ++i)
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if (!s.count(word.substr(0, i)))
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return false;
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return true;
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}
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};
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```
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### **Go**
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```go
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func longestWord(words []string) string {
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s := make(map[string]bool)
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for _, w := range words {
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s[w] = true
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}
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cnt := 0
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ans := ""
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check := func(word string) bool {
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for i, n := 1, len(word); i < n; i++ {
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if !s[word[:i]] {
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return false
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}
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}
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return true
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}
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for w, _ := range s {
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n := len(w)
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if check(w) {
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if cnt < n {
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cnt, ans = n, w
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} else if cnt == n && w < ans {
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ans = w
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}
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}
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}
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return ans
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}
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```
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### **...**
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```

‎solution/0700-0799/0720.Longest Word in Dictionary/README_EN.md

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### **Python3**
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```python
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class Solution:
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def longestWord(self, words: List[str]) -> str:
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cnt, ans = 0, ''
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s = set(words)
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for w in s:
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n = len(w)
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if all(w[:i] in s for i in range(1, n)):
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if cnt < n:
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cnt, ans = n, w
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elif cnt == n and w < ans:
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ans = w
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return ans
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```
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### **Java**
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```java
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class Solution {
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private Set<String> s;
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public String longestWord(String[] words) {
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s = new HashSet<>(Arrays.asList(words));
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int cnt = 0;
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String ans = "";
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for (String w : s) {
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int n = w.length();
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if (check(w)) {
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if (cnt < n) {
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cnt = n;
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ans = w;
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} else if (cnt == n && w.compareTo(ans) < 0) {
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ans = w;
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}
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}
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}
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return ans;
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}
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private boolean check(String word) {
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for (int i = 1, n = word.length(); i < n; ++i) {
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if (!s.contains(word.substring(0, i))) {
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return false;
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}
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}
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return true;
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}
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}
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```
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### **TypeScript**
@@ -101,6 +141,72 @@ impl Solution {
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}
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```
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### **C++**
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```cpp
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class Solution {
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public:
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string longestWord(vector<string>& words) {
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unordered_set<string> s(words.begin(), words.end());
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int cnt = 0;
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string ans = "";
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for (auto w : s)
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{
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int n = w.size();
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if (check(w, s))
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{
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if (cnt < n)
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{
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cnt = n;
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ans = w;
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}
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else if (cnt == n && w < ans) ans = w;
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}
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}
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return ans;
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}
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bool check(string& word, unordered_set<string>& s) {
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for (int i = 1, n = word.size(); i < n; ++i)
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if (!s.count(word.substr(0, i)))
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return false;
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return true;
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}
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};
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```
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### **Go**
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```go
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func longestWord(words []string) string {
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s := make(map[string]bool)
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for _, w := range words {
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s[w] = true
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}
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cnt := 0
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ans := ""
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check := func(word string) bool {
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for i, n := 1, len(word); i < n; i++ {
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if !s[word[:i]] {
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return false
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}
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}
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return true
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}
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for w, _ := range s {
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n := len(w)
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if check(w) {
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if cnt < n {
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cnt, ans = n, w
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} else if cnt == n && w < ans {
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ans = w
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}
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}
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}
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return ans
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}
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```
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### **...**
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```

‎solution/0700-0799/0720.Longest Word in Dictionary/Solution.cpp

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@@ -0,0 +1,29 @@
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class Solution {
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public:
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string longestWord(vector<string>& words) {
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unordered_set<string> s(words.begin(), words.end());
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int cnt = 0;
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string ans = "";
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for (auto w : s)
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{
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int n = w.size();
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if (check(w, s))
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{
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if (cnt < n)
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{
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cnt = n;
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ans = w;
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}
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else if (cnt == n && w < ans) ans = w;
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}
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}
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return ans;
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}
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bool check(string& word, unordered_set<string>& s) {
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for (int i = 1, n = word.size(); i < n; ++i)
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if (!s.count(word.substr(0, i)))
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return false;
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return true;
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}
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};

‎solution/0700-0799/0720.Longest Word in Dictionary/Solution.go

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@@ -0,0 +1,27 @@
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func longestWord(words []string) string {
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s := make(map[string]bool)
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for _, w := range words {
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s[w] = true
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}
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cnt := 0
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ans := ""
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check := func(word string) bool {
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for i, n := 1, len(word); i < n; i++ {
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if !s[word[:i]] {
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return false
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}
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}
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return true
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}
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for w, _ := range s {
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n := len(w)
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if check(w) {
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if cnt < n {
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cnt, ans = n, w
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} else if cnt == n && w < ans {
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ans = w
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}
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}
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}
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return ans
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}

‎solution/0700-0799/0720.Longest Word in Dictionary/Solution.java

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,30 @@
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class Solution {
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private Set<String> s;
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public String longestWord(String[] words) {
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s = new HashSet<>(Arrays.asList(words));
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int cnt = 0;
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String ans = "";
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for (String w : s) {
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int n = w.length();
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if (check(w)) {
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if (cnt < n) {
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cnt = n;
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ans = w;
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} else if (cnt == n && w.compareTo(ans) < 0) {
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ans = w;
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}
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}
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}
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return ans;
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}
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private boolean check(String word) {
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for (int i = 1, n = word.length(); i < n; ++i) {
24+
if (!s.contains(word.substring(0, i))) {
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return false;
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}
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}
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return true;
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}
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}

‎solution/0700-0799/0720.Longest Word in Dictionary/Solution.py

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@@ -0,0 +1,12 @@
1+
class Solution:
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def longestWord(self, words: List[str]) -> str:
3+
cnt, ans = 0, ''
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s = set(words)
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for w in s:
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n = len(w)
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if all(w[:i] in s for i in range(1, n)):
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if cnt < n:
9+
cnt, ans = n, w
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elif cnt == n and w < ans:
11+
ans = w
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return ans

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