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feat: update leetcode solutions: No.0017. Letter Combinations of a Phone Number
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Diff for: ‎README.md

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@@ -69,6 +69,7 @@
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### 字符串
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- [无重复字符的最长子串](/solution/0000-0099/0003.Longest%20Substring%20Without%20Repeating%20Characters/README.md)
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- [最长公共前缀](/solution/0000-0099/0014.Longest%20Common%20Prefix/README.md)
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- [反转字符串中的元音字母](/solution/0300-0399/0345.Reverse%20Vowels%20of%20a%20String/README.md)
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- [字符串转换整数 (atoi)](/solution/0000-0099/0008.String%20to%20Integer%20%28atoi%29/README.md)
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- [赎金信](/solution/0300-0399/0383.Ransom%20Note/README.md)

Diff for: ‎README_EN.md

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@@ -68,6 +68,7 @@ Complete solutions to [LeetCode](https://leetcode-cn.com/problemset/all/), [LCOF
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### Strings
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- [Longest Substring Without Repeating Characters](/solution/0000-0099/0003.Longest%20Substring%20Without%20Repeating%20Characters/README_EN.md)
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- [Longest Common Prefix](/solution/0000-0099/0014.Longest%20Common%20Prefix/README_EN.md)
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- [Reverse Vowels of a String](/solution/0300-0399/0345.Reverse%20Vowels%20of%20a%20String/README_EN.md)
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- [String to Integer (atoi)](/solution/0000-0099/0008.String%20to%20Integer%20%28atoi%29/README_EN.md)
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- [Ransom Note](/solution/0300-0399/0383.Ransom%20Note/README_EN.md)

Diff for: ‎solution/0000-0099/0017.Letter Combinations of a Phone Number/README.md

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Original file line numberDiff line numberDiff line change
@@ -31,15 +31,60 @@
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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 letterCombinations(self, digits: str) -> List[str]:
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n = len(digits)
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if n == 0:
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return []
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chars = ['abc', 'def', 'ghi', 'jkl', 'mno', 'pqrs', 'tuv', 'wxyz']
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strs = [chars[int(d) - 2] for d in digits]
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res = []
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for s in strs:
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if not res:
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res = list(s)
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else:
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cache = []
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for item in res:
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for letter in s:
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cache.append(item + letter)
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res = cache
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return res
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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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public List<String> letterCombinations(String digits) {
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int n;
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if ((n = digits.length()) == 0) return Collections.emptyList();
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List<String> chars = Arrays.asList("abc", "def", "ghi", "jkl", "mno", "pqrs", "tuv", "wxyz");
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List<String> strs = new ArrayList<>();
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for (char c : digits.toCharArray()) {
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strs.add(chars.get(c - '0' - 2));
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}
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List<String> res = new ArrayList<>();
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for (String str : strs) {
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if (res.size() == 0) {
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for (char c : str.toCharArray()) {
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res.add(String.valueOf(c));
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}
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} else {
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List<String> cache = new ArrayList<>();
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for (String item : res) {
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for (char c : str.toCharArray()) {
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cache.add(item + String.valueOf(c));
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}
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}
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res = cache;
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}
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}
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return res;
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}
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}
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```
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### **...**

Diff for: ‎solution/0000-0099/0017.Letter Combinations of a Phone Number/README_EN.md

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Original file line numberDiff line numberDiff line change
@@ -31,13 +31,58 @@
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### **Python3**
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```python
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class Solution:
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def letterCombinations(self, digits: str) -> List[str]:
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n = len(digits)
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if n == 0:
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return []
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chars = ['abc', 'def', 'ghi', 'jkl', 'mno', 'pqrs', 'tuv', 'wxyz']
40+
strs = [chars[int(d) - 2] for d in digits]
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res = []
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for s in strs:
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if not res:
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res = list(s)
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else:
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cache = []
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for item in res:
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for letter in s:
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cache.append(item + letter)
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res = cache
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return res
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```
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### **Java**
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```java
40-
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class Solution {
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public List<String> letterCombinations(String digits) {
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int n;
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if ((n = digits.length()) == 0) return Collections.emptyList();
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List<String> chars = Arrays.asList("abc", "def", "ghi", "jkl", "mno", "pqrs", "tuv", "wxyz");
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List<String> strs = new ArrayList<>();
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for (char c : digits.toCharArray()) {
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strs.add(chars.get(c - '0' - 2));
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}
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List<String> res = new ArrayList<>();
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for (String str : strs) {
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if (res.size() == 0) {
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for (char c : str.toCharArray()) {
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res.add(String.valueOf(c));
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}
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} else {
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List<String> cache = new ArrayList<>();
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for (String item : res) {
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for (char c : str.toCharArray()) {
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cache.add(item + String.valueOf(c));
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}
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}
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res = cache;
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}
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}
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return res;
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}
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}
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```
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### **...**

Diff for: ‎solution/0000-0099/0017.Letter Combinations of a Phone Number/Solution.java

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Original file line numberDiff line numberDiff line change
@@ -1,30 +1,29 @@
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class Solution {
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public List<String> letterCombinations(String digits) {
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char[] cs = digits.toCharArray();
4-
List<String> result = new ArrayList<>();
5-
for (char a : cs) {
6-
char[] charArray;
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switch (a) {
8-
case '2': charArray = new char[]{'a','b','c'}; break;
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case '3': charArray = new char[]{'d','e','f'}; break;
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case '4': charArray = new char[]{'g','h','i'}; break;
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case '5': charArray = new char[]{'j','k','l'}; break;
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case '6': charArray = new char[]{'m','n','o'}; break;
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case '7': charArray = new char[]{'p','q','r','s'}; break;
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case '8': charArray = new char[]{'t','u','v'}; break;
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case '9': charArray = new char[]{'w','x','y','z'}; break;
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default: return null;
17-
}
18-
if (result.size() == 0) {
19-
for (char aCharArray : charArray) result.add(String.valueOf(aCharArray));
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int n;
4+
if ((n = digits.length()) == 0) return Collections.emptyList();
5+
List<String> chars = Arrays.asList("abc", "def", "ghi", "jkl", "mno", "pqrs", "tuv", "wxyz");
6+
7+
List<String> strs = new ArrayList<>();
8+
for (char c : digits.toCharArray()) {
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strs.add(chars.get(c - '0' - 2));
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}
11+
List<String> res = new ArrayList<>();
12+
for (String str : strs) {
13+
if (res.size() == 0) {
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for (char c : str.toCharArray()) {
15+
res.add(String.valueOf(c));
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}
2017
} else {
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List<String> cache = new ArrayList<>();
22-
for (String string : result) {
23-
for (char aCharArray : charArray) cache.add(string + aCharArray);
19+
for (String item : res) {
20+
for (char c : str.toCharArray()) {
21+
cache.add(item + String.valueOf(c));
22+
}
2423
}
25-
result = cache;
24+
res = cache;
2625
}
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}
28-
return result;
27+
return res;
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}
30-
}
29+
}

Diff for: ‎solution/0000-0099/0017.Letter Combinations of a Phone Number/Solution.py

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@@ -0,0 +1,18 @@
1+
class Solution:
2+
def letterCombinations(self, digits: str) -> List[str]:
3+
n = len(digits)
4+
if n == 0:
5+
return []
6+
chars = ['abc', 'def', 'ghi', 'jkl', 'mno', 'pqrs', 'tuv', 'wxyz']
7+
strs = [chars[int(d) - 2] for d in digits]
8+
res = []
9+
for s in strs:
10+
if not res:
11+
res = list(s)
12+
else:
13+
cache = []
14+
for item in res:
15+
for letter in s:
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cache.append(item + letter)
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res = cache
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return res

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