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Nov 28, 2024
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feat: add solutions to lc problem: No.1309 #3821

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107 changes: 74 additions & 33 deletions solution/1300-1399/1309.Decrypt String from Alphabet to Integer Mapping/README.md
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Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -62,7 +62,15 @@ tags:

<!-- solution:start -->

### 方法一
### 方法一：模拟

我们直接模拟即可。

遍历字符串 $s$，对于当前遍历到的下标 $i$，如果 $i + 2 < n$ 且 $s[i + 2]$ 为 `#`，则将 $s[i]$ 和 $s[i + 1]$ 组成的字符串转换为整数，加上 `a` 的 ASCII 码值减去 1，然后转换为字符，添加到结果数组中，并将 $i$ 增加 3；否则，将 $s[i]$ 转换为整数，加上 `a` 的 ASCII 码值减去 1，然后转换为字符，添加到结果数组中，并将 $i$ 增加 1。

最后将结果数组转换为字符串返回即可。

时间复杂度 $O(n)$，空间复杂度 $O(n)$。其中 $n$ 为字符串 $s$ 的长度。

<!-- tabs:start -->

Expand All @@ -71,19 +79,16 @@ tags:
```python
class Solution:
def freqAlphabets(self, s: str) -> str:
def get(s):
return chr(ord('a') + int(s) - 1)

ans = []
i, n = 0, len(s)
res = []
while i < n:
if i + 2 < n and s[i + 2] == '#':
res.append(get(s[i : i + 2]))
if i + 2 < n and s[i + 2] == "#":
ans.append(chr(int(s[i : i + 2]) + ord("a") - 1))
i += 3
else:
res.append(get(s[i]))
ans.append(chr(int(s[i]) + ord("a") - 1))
i += 1
return ''.join(res)
return "".join(ans)
```

#### Java
Expand All @@ -92,42 +97,78 @@ class Solution:
class Solution {
public String freqAlphabets(String s) {
int i = 0, n = s.length();
StringBuilder res = new StringBuilder();
StringBuilder ans = new StringBuilder();
while (i < n) {
if (i + 2 < n && s.charAt(i + 2) == '#') {
res.append(get(s.substring(i, i + 2)));
ans.append((char) ('a' + Integer.parseInt(s.substring(i, i + 2)) - 1));
i += 3;
} else {
res.append(get(s.substring(i, i + 1)));
i += 1;
ans.append((char) ('a' + Integer.parseInt(s.substring(i, i + 1)) - 1));
i++;
}
}
return res.toString();
return ans.toString();
}
}
```

#### C++

private char get(String s) {
return (char) ('a' + Integer.parseInt(s) - 1);
```cpp
class Solution {
public:
string freqAlphabets(string s) {
string ans = "";
int i = 0, n = s.size();
while (i < n) {
if (i + 2 < n && s[i + 2] == '#') {
ans += char(stoi(s.substr(i, 2)) + 'a' - 1);
i += 3;
} else {
ans += char(s[i] - '0' + 'a' - 1);
i += 1;
}
}
return ans;
}
};
```

#### Go

```go
func freqAlphabets(s string) string {
var ans []byte
for i, n := 0, len(s); i < n; {
if i+2 < n && s[i+2] == '#' {
num := (int(s[i])-'0')*10 + int(s[i+1]) - '0'
ans = append(ans, byte(num+int('a')-1))
i += 3
} else {
num := int(s[i]) - '0'
ans = append(ans, byte(num+int('a')-1))
i += 1
}
}
return string(ans)
}
```

#### TypeScript

```ts
function freqAlphabets(s: string): string {
const n = s.length;
const ans = [];
let i = 0;
while (i < n) {
if (s[i + 2] == '#') {
ans.push(s.slice(i, i + 2));
const ans: string[] = [];
for (let i = 0, n = s.length; i < n; ) {
if (i + 2 < n && s[i + 2] === '#') {
ans.push(String.fromCharCode(96 + +s.slice(i, i + 2)));
i += 3;
} else {
ans.push(s[i]);
i += 1;
ans.push(String.fromCharCode(96 + +s[i]));
i++;
}
}
return ans.map(c => String.fromCharCode('a'.charCodeAt(0) + Number(c) - 1)).join('');
return ans.join('');
}
```

Expand All @@ -137,21 +178,21 @@ function freqAlphabets(s: string): string {
impl Solution {
pub fn freq_alphabets(s: String) -> String {
let s = s.as_bytes();
let n = s.len();
let mut res = String::new();
let mut ans = String::new();
let mut i = 0;
let n = s.len();
while i < n {
let code: u8;
if s.get(i + 2).is_some() && s[i + 2] == b'#' {
code = (s[i] - b'0') * 10 + s[i + 1];
if i + 2 < n && s[i + 2] == b'#' {
let num = (s[i] - b'0') * 10 + (s[i + 1] - b'0');
ans.push((96 + num) as char);
i += 3;
} else {
code = s[i];
let num = s[i] - b'0';
ans.push((96 + num) as char);
i += 1;
}
res.push(char::from(('a' as u8) + code - b'1'));
}
res
ans
}
}
```
Expand Down
107 changes: 74 additions & 33 deletions ...ion/1300-1399/1309.Decrypt String from Alphabet to Integer Mapping/README_EN.md
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Original file line number Diff line number Diff line change
Expand Up @@ -60,7 +60,15 @@ tags:

<!-- solution:start -->

### Solution 1
### Solution 1: Simulation

We can directly simulate the process.

Traverse the string $s$. For the current index $i$, if $i + 2 < n$ and $s[i + 2]$ is `#`, then convert the substring formed by $s[i]$ and $s[i + 1]$ to an integer, add the ASCII value of `a` minus 1, convert it to a character, add it to the result array, and increment $i$ by 3. Otherwise, convert $s[i]$ to an integer, add the ASCII value of `a` minus 1, convert it to a character, add it to the result array, and increment $i$ by 1.

Finally, convert the result array to a string and return it.

The time complexity is $O(n)$, and the space complexity is $O(n)$. Here, $n$ is the length of the string $s$.

<!-- tabs:start -->

Expand All @@ -69,19 +77,16 @@ tags:
```python
class Solution:
def freqAlphabets(self, s: str) -> str:
def get(s):
return chr(ord('a') + int(s) - 1)

ans = []
i, n = 0, len(s)
res = []
while i < n:
if i + 2 < n and s[i + 2] == '#':
res.append(get(s[i : i + 2]))
if i + 2 < n and s[i + 2] == "#":
ans.append(chr(int(s[i : i + 2]) + ord("a") - 1))
i += 3
else:
res.append(get(s[i]))
ans.append(chr(int(s[i]) + ord("a") - 1))
i += 1
return ''.join(res)
return "".join(ans)
```

#### Java
Expand All @@ -90,42 +95,78 @@ class Solution:
class Solution {
public String freqAlphabets(String s) {
int i = 0, n = s.length();
StringBuilder res = new StringBuilder();
StringBuilder ans = new StringBuilder();
while (i < n) {
if (i + 2 < n && s.charAt(i + 2) == '#') {
res.append(get(s.substring(i, i + 2)));
ans.append((char) ('a' + Integer.parseInt(s.substring(i, i + 2)) - 1));
i += 3;
} else {
res.append(get(s.substring(i, i + 1)));
i += 1;
ans.append((char) ('a' + Integer.parseInt(s.substring(i, i + 1)) - 1));
i++;
}
}
return res.toString();
return ans.toString();
}
}
```

#### C++

private char get(String s) {
return (char) ('a' + Integer.parseInt(s) - 1);
```cpp
class Solution {
public:
string freqAlphabets(string s) {
string ans = "";
int i = 0, n = s.size();
while (i < n) {
if (i + 2 < n && s[i + 2] == '#') {
ans += char(stoi(s.substr(i, 2)) + 'a' - 1);
i += 3;
} else {
ans += char(s[i] - '0' + 'a' - 1);
i += 1;
}
}
return ans;
}
};
```

#### Go

```go
func freqAlphabets(s string) string {
var ans []byte
for i, n := 0, len(s); i < n; {
if i+2 < n && s[i+2] == '#' {
num := (int(s[i])-'0')*10 + int(s[i+1]) - '0'
ans = append(ans, byte(num+int('a')-1))
i += 3
} else {
num := int(s[i]) - '0'
ans = append(ans, byte(num+int('a')-1))
i += 1
}
}
return string(ans)
}
```

#### TypeScript

```ts
function freqAlphabets(s: string): string {
const n = s.length;
const ans = [];
let i = 0;
while (i < n) {
if (s[i + 2] == '#') {
ans.push(s.slice(i, i + 2));
const ans: string[] = [];
for (let i = 0, n = s.length; i < n; ) {
if (i + 2 < n && s[i + 2] === '#') {
ans.push(String.fromCharCode(96 + +s.slice(i, i + 2)));
i += 3;
} else {
ans.push(s[i]);
i += 1;
ans.push(String.fromCharCode(96 + +s[i]));
i++;
}
}
return ans.map(c => String.fromCharCode('a'.charCodeAt(0) + Number(c) - 1)).join('');
return ans.join('');
}
```

Expand All @@ -135,21 +176,21 @@ function freqAlphabets(s: string): string {
impl Solution {
pub fn freq_alphabets(s: String) -> String {
let s = s.as_bytes();
let n = s.len();
let mut res = String::new();
let mut ans = String::new();
let mut i = 0;
let n = s.len();
while i < n {
let code: u8;
if s.get(i + 2).is_some() && s[i + 2] == b'#' {
code = (s[i] - b'0') * 10 + s[i + 1];
if i + 2 < n && s[i + 2] == b'#' {
let num = (s[i] - b'0') * 10 + (s[i + 1] - b'0');
ans.push((96 + num) as char);
i += 3;
} else {
code = s[i];
let num = s[i] - b'0';
ans.push((96 + num) as char);
i += 1;
}
res.push(char::from(('a' as u8) + code - b'1'));
}
res
ans
}
}
```
Expand Down
17 changes: 17 additions & 0 deletions solution/1300-1399/1309.Decrypt String from Alphabet to Integer Mapping/Solution.cpp
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Original file line number Diff line number Diff line change
@@ -0,0 +1,17 @@
class Solution {
public:
string freqAlphabets(string s) {
string ans = "";
int i = 0, n = s.size();
while (i < n) {
if (i + 2 < n && s[i + 2] == '#') {
ans += char(stoi(s.substr(i, 2)) + 'a' - 1);
i += 3;
} else {
ans += char(s[i] - '0' + 'a' - 1);
i += 1;
}
}
return ans;
}
};
15 changes: 15 additions & 0 deletions solution/1300-1399/1309.Decrypt String from Alphabet to Integer Mapping/Solution.go
View file
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Original file line number Diff line number Diff line change
@@ -0,0 +1,15 @@
func freqAlphabets(s string) string {
var ans []byte
for i, n := 0, len(s); i < n; {
if i+2 < n && s[i+2] == '#' {
num := (int(s[i])-'0')*10 + int(s[i+1]) - '0'
ans = append(ans, byte(num+int('a')-1))
i += 3
} else {
num := int(s[i]) - '0'
ans = append(ans, byte(num+int('a')-1))
i += 1
}
}
return string(ans)
}
16 changes: 6 additions & 10 deletions solution/1300-1399/1309.Decrypt String from Alphabet to Integer Mapping/Solution.java
View file
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Original file line number Diff line number Diff line change
@@ -1,20 +1,16 @@
class Solution {
public String freqAlphabets(String s) {
int i = 0, n = s.length();
StringBuilder res = new StringBuilder();
StringBuilder ans = new StringBuilder();
while (i < n) {
if (i + 2 < n && s.charAt(i + 2) == '#') {
res.append(get(s.substring(i, i + 2)));
ans.append((char) ('a' + Integer.parseInt(s.substring(i, i + 2)) - 1));
i += 3;
} else {
res.append(get(s.substring(i, i + 1)));
i += 1;
ans.append((char) ('a' + Integer.parseInt(s.substring(i, i + 1)) - 1));
i++;
}
}
return res.toString();
return ans.toString();
}

private char get(String s) {
return (char) ('a' + Integer.parseInt(s) - 1);
}
}
}
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