diff --git a/solution/1300-1399/1309.Decrypt String from Alphabet to Integer Mapping/README.md b/solution/1300-1399/1309.Decrypt String from Alphabet to Integer Mapping/README.md index c1d3a2ad2757d..5e36aa13411e6 100644 --- a/solution/1300-1399/1309.Decrypt String from Alphabet to Integer Mapping/README.md +++ b/solution/1300-1399/1309.Decrypt String from Alphabet to Integer Mapping/README.md @@ -62,7 +62,15 @@ tags: -### 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。 @@ -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 @@ -92,22 +97,60 @@ 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) } ``` @@ -115,19 +158,17 @@ class Solution { ```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(''); } ``` @@ -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 } } ``` diff --git a/solution/1300-1399/1309.Decrypt String from Alphabet to Integer Mapping/README_EN.md b/solution/1300-1399/1309.Decrypt String from Alphabet to Integer Mapping/README_EN.md index 1a1e65de8e681..7d61ce8908cfc 100644 --- a/solution/1300-1399/1309.Decrypt String from Alphabet to Integer Mapping/README_EN.md +++ b/solution/1300-1399/1309.Decrypt String from Alphabet to Integer Mapping/README_EN.md @@ -60,7 +60,15 @@ tags: -### 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 $s$. @@ -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 @@ -90,22 +95,60 @@ 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) } ``` @@ -113,19 +156,17 @@ class Solution { ```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(''); } ``` @@ -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 } } ``` diff --git a/solution/1300-1399/1309.Decrypt String from Alphabet to Integer Mapping/Solution.cpp b/solution/1300-1399/1309.Decrypt String from Alphabet to Integer Mapping/Solution.cpp new file mode 100644 index 0000000000000..0a29e04551ea8 --- /dev/null +++ b/solution/1300-1399/1309.Decrypt String from Alphabet to Integer Mapping/Solution.cpp @@ -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; + } +}; diff --git a/solution/1300-1399/1309.Decrypt String from Alphabet to Integer Mapping/Solution.go b/solution/1300-1399/1309.Decrypt String from Alphabet to Integer Mapping/Solution.go new file mode 100644 index 0000000000000..44c5fb42c7530 --- /dev/null +++ b/solution/1300-1399/1309.Decrypt String from Alphabet to Integer Mapping/Solution.go @@ -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) +} diff --git a/solution/1300-1399/1309.Decrypt String from Alphabet to Integer Mapping/Solution.java b/solution/1300-1399/1309.Decrypt String from Alphabet to Integer Mapping/Solution.java index 068dba6d70fb7..db2597aa0414f 100644 --- a/solution/1300-1399/1309.Decrypt String from Alphabet to Integer Mapping/Solution.java +++ b/solution/1300-1399/1309.Decrypt String from Alphabet to Integer Mapping/Solution.java @@ -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); - } -} \ No newline at end of file +} diff --git a/solution/1300-1399/1309.Decrypt String from Alphabet to Integer Mapping/Solution.py b/solution/1300-1399/1309.Decrypt String from Alphabet to Integer Mapping/Solution.py index 7bc92e0f9085c..54312b76cbe18 100644 --- a/solution/1300-1399/1309.Decrypt String from Alphabet to Integer Mapping/Solution.py +++ b/solution/1300-1399/1309.Decrypt String from Alphabet to Integer Mapping/Solution.py @@ -1,15 +1,12 @@ 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) diff --git a/solution/1300-1399/1309.Decrypt String from Alphabet to Integer Mapping/Solution.rs b/solution/1300-1399/1309.Decrypt String from Alphabet to Integer Mapping/Solution.rs index d0a3d25effee3..85e9250fad523 100644 --- a/solution/1300-1399/1309.Decrypt String from Alphabet to Integer Mapping/Solution.rs +++ b/solution/1300-1399/1309.Decrypt String from Alphabet to Integer Mapping/Solution.rs @@ -1,20 +1,20 @@ 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 } } diff --git a/solution/1300-1399/1309.Decrypt String from Alphabet to Integer Mapping/Solution.ts b/solution/1300-1399/1309.Decrypt String from Alphabet to Integer Mapping/Solution.ts index 394c5c35d651b..a688564202195 100644 --- a/solution/1300-1399/1309.Decrypt String from Alphabet to Integer Mapping/Solution.ts +++ b/solution/1300-1399/1309.Decrypt String from Alphabet to Integer Mapping/Solution.ts @@ -1,15 +1,13 @@ 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(''); }