diff --git a/solution/1900-1999/1957.Delete Characters to Make Fancy String/README.md b/solution/1900-1999/1957.Delete Characters to Make Fancy String/README.md index fbfab3d1aea3c..ec802af1344cc 100644 --- a/solution/1900-1999/1957.Delete Characters to Make Fancy String/README.md +++ b/solution/1900-1999/1957.Delete Characters to Make Fancy String/README.md @@ -72,11 +72,11 @@ tags: ### 方法一：模拟 -我们可以遍历字符串 $s$，并使用一个数组 $\textit{ans}$ 记录当前的答案。对于每一个字符 $c$，如果 $\textit{ans}$ 的长度小于 $2$ 或者 $\textit{ans}$ 的最后两个字符不等于 $c$，我们就将 $c$ 添加到 $\textit{ans}$ 中。 +我们可以遍历字符串 $s$，并使用一个数组 $\textit{ans}$ 记录当前的答案。对于每一个字符 $\textit{s[i]}$，如果 $i \lt 2$ 或者 $s[i]$ 与 $s[i - 1]$ 不等，或者 $s[i]$ 与 $s[i - 2]$ 不等，我们就将 $s[i]$ 添加到 $\textit{ans}$ 中。 最后，我们将 $\textit{ans}$ 中的字符连接起来，就得到了答案。 -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。 +时间复杂度 $O(n)$，其中 $n$ 为字符串 $s$ 的长度。忽略答案的空间消耗，空间复杂度 $O(1)$。 @@ -86,8 +86,8 @@ tags: class Solution: def makeFancyString(self, s: str) -> str: ans = [] - for c in s: - if len(ans) < 2 or ans[-1] != c or ans[-2] != c: + for i, c in enumerate(s): + if i < 2 or c != s[i - 1] or c != s[i - 2]: ans.append(c) return "".join(ans) ``` @@ -98,9 +98,9 @@ class Solution: class Solution { public String makeFancyString(String s) { StringBuilder ans = new StringBuilder(); - for (char c : s.toCharArray()) { - int n = ans.length(); - if (n < 2 || c != ans.charAt(n - 1) || c != ans.charAt(n - 2)) { + for (int i = 0; i < s.length(); ++i) { + char c = s.charAt(i); + if (i < 2 || c != s.charAt(i - 1) || c != s.charAt(i - 2)) { ans.append(c); } } @@ -116,9 +116,9 @@ class Solution { public: string makeFancyString(string s) { string ans = ""; - for (char& c : s) { - int n = ans.size(); - if (n < 2 || ans[n - 1] != c || ans[n - 2] != c) { + for (int i = 0; i < s.length(); ++i) { + char c = s[i]; + if (i < 2 || c != s[i - 1] || c != s[i - 2]) { ans += c; } } @@ -131,9 +131,9 @@ public: ```go func makeFancyString(s string) string { - ans := []rune{} - for _, c := range s { - if n := len(ans); n < 2 || c != ans[n-1] || c != ans[n-2] { + ans := []byte{} + for i, ch := range s { + if c := byte(ch); i < 2 || c != s[i-1] || c != s[i-2] { ans = append(ans, c) } } @@ -145,28 +145,32 @@ func makeFancyString(s string) string { ```ts function makeFancyString(s: string): string { - let [n, ans] = [s.length, '']; - for (let i = 0; i < n; i++) { + const ans: string[] = []; + for (let i = 0; i < s.length; ++i) { if (s[i] !== s[i - 1] || s[i] !== s[i - 2]) { - ans += s[i]; + ans.push(s[i]); } } - return ans; + return ans.join(''); } ``` #### JavaScript ```js -function makeFancyString(s) { - let [n, ans] = [s.length, '']; - for (let i = 0; i < n; i++) { +/** + * @param {string} s + * @return {string} + */ +var makeFancyString = function (s) { + const ans = []; + for (let i = 0; i < s.length; ++i) { if (s[i] !== s[i - 1] || s[i] !== s[i - 2]) { - ans += s[i]; + ans.push(s[i]); } } - return ans; -} + return ans.join(''); +}; ``` #### PHP @@ -178,17 +182,14 @@ class Solution { * @return String */ function makeFancyString($s) { - $ans = []; - $length = strlen($s); - - for ($i = 0; $i < $length; $i++) { - $n = count($ans); - if ($n < 2 || $s[$i] !== $ans[$n - 1] || $s[$i] !== $ans[$n - 2]) { - $ans[] = $s[$i]; + $ans = ''; + for ($i = 0; $i < strlen($s); $i++) { + $c = $s[$i]; + if ($i < 2 || $c !== $s[$i - 1] || $c !== $s[$i - 2]) { + $ans .= $c; } } - - return implode('', $ans); + return $ans; } } ``` diff --git a/solution/1900-1999/1957.Delete Characters to Make Fancy String/README_EN.md b/solution/1900-1999/1957.Delete Characters to Make Fancy String/README_EN.md index 466d7474105a2..2879eb33fac38 100644 --- a/solution/1900-1999/1957.Delete Characters to Make Fancy String/README_EN.md +++ b/solution/1900-1999/1957.Delete Characters to Make Fancy String/README_EN.md @@ -70,11 +70,11 @@ No three consecutive characters are equal, so return "aabaa". ### Solution 1: Simulation -We can traverse the string $s$ and use an array $\textit{ans}$ to record the current answer. For each character $c$, if the length of $\textit{ans}$ is less than $2$ or the last two characters of $\textit{ans}$ are not equal to $c$, we add $c$ to $\textit{ans}$. +We can iterate through the string $s$ and use an array $\textit{ans}$ to record the current answer. For each character $\textit{s[i]}$, if $i < 2$ or $s[i]$ is not equal to $s[i - 1]$, or $s[i]$ is not equal to $s[i - 2]$, we add $s[i]$ to $\textit{ans}$. Finally, we concatenate the characters in $\textit{ans}$ to get the answer. -The time complexity is $O(n)$, and the space complexity is $O(n)$. Here, $n$ is the length of the string $s$. +The time complexity is $O(n)$, where $n$ is the length of the string $s$. Ignoring the space consumption of the answer, the space complexity is $O(1)$. @@ -84,8 +84,8 @@ The time complexity is $O(n)$, and the space complexity is $O(n)$. Here, $n$ is class Solution: def makeFancyString(self, s: str) -> str: ans = [] - for c in s: - if len(ans) < 2 or ans[-1] != c or ans[-2] != c: + for i, c in enumerate(s): + if i < 2 or c != s[i - 1] or c != s[i - 2]: ans.append(c) return "".join(ans) ``` @@ -96,9 +96,9 @@ class Solution: class Solution { public String makeFancyString(String s) { StringBuilder ans = new StringBuilder(); - for (char c : s.toCharArray()) { - int n = ans.length(); - if (n < 2 || c != ans.charAt(n - 1) || c != ans.charAt(n - 2)) { + for (int i = 0; i < s.length(); ++i) { + char c = s.charAt(i); + if (i < 2 || c != s.charAt(i - 1) || c != s.charAt(i - 2)) { ans.append(c); } } @@ -114,9 +114,9 @@ class Solution { public: string makeFancyString(string s) { string ans = ""; - for (char& c : s) { - int n = ans.size(); - if (n < 2 || ans[n - 1] != c || ans[n - 2] != c) { + for (int i = 0; i < s.length(); ++i) { + char c = s[i]; + if (i < 2 || c != s[i - 1] || c != s[i - 2]) { ans += c; } } @@ -129,9 +129,9 @@ public: ```go func makeFancyString(s string) string { - ans := []rune{} - for _, c := range s { - if n := len(ans); n < 2 || c != ans[n-1] || c != ans[n-2] { + ans := []byte{} + for i, ch := range s { + if c := byte(ch); i < 2 || c != s[i-1] || c != s[i-2] { ans = append(ans, c) } } @@ -143,28 +143,32 @@ func makeFancyString(s string) string { ```ts function makeFancyString(s: string): string { - let [n, ans] = [s.length, '']; - for (let i = 0; i < n; i++) { + const ans: string[] = []; + for (let i = 0; i < s.length; ++i) { if (s[i] !== s[i - 1] || s[i] !== s[i - 2]) { - ans += s[i]; + ans.push(s[i]); } } - return ans; + return ans.join(''); } ``` #### JavaScript ```js -function makeFancyString(s) { - let [n, ans] = [s.length, '']; - for (let i = 0; i < n; i++) { +/** + * @param {string} s + * @return {string} + */ +var makeFancyString = function (s) { + const ans = []; + for (let i = 0; i < s.length; ++i) { if (s[i] !== s[i - 1] || s[i] !== s[i - 2]) { - ans += s[i]; + ans.push(s[i]); } } - return ans; -} + return ans.join(''); +}; ``` #### PHP @@ -176,17 +180,14 @@ class Solution { * @return String */ function makeFancyString($s) { - $ans = []; - $length = strlen($s); - - for ($i = 0; $i < $length; $i++) { - $n = count($ans); - if ($n < 2 || $s[$i] !== $ans[$n - 1] || $s[$i] !== $ans[$n - 2]) { - $ans[] = $s[$i]; + $ans = ''; + for ($i = 0; $i < strlen($s); $i++) { + $c = $s[$i]; + if ($i < 2 || $c !== $s[$i - 1] || $c !== $s[$i - 2]) { + $ans .= $c; } } - - return implode('', $ans); + return $ans; } } ``` diff --git a/solution/1900-1999/1957.Delete Characters to Make Fancy String/Solution.cpp b/solution/1900-1999/1957.Delete Characters to Make Fancy String/Solution.cpp index 79416b151e375..450b000663202 100644 --- a/solution/1900-1999/1957.Delete Characters to Make Fancy String/Solution.cpp +++ b/solution/1900-1999/1957.Delete Characters to Make Fancy String/Solution.cpp @@ -2,9 +2,9 @@ class Solution { public: string makeFancyString(string s) { string ans = ""; - for (char& c : s) { - int n = ans.size(); - if (n < 2 || ans[n - 1] != c || ans[n - 2] != c) { + for (int i = 0; i < s.length(); ++i) { + char c = s[i]; + if (i < 2 || c != s[i - 1] || c != s[i - 2]) { ans += c; } } diff --git a/solution/1900-1999/1957.Delete Characters to Make Fancy String/Solution.go b/solution/1900-1999/1957.Delete Characters to Make Fancy String/Solution.go index b472925d7fd9e..3118be7e97ed2 100644 --- a/solution/1900-1999/1957.Delete Characters to Make Fancy String/Solution.go +++ b/solution/1900-1999/1957.Delete Characters to Make Fancy String/Solution.go @@ -1,7 +1,7 @@ func makeFancyString(s string) string { - ans := []rune{} - for _, c := range s { - if n := len(ans); n < 2 || c != ans[n-1] || c != ans[n-2] { + ans := []byte{} + for i, ch := range s { + if c := byte(ch); i < 2 || c != s[i-1] || c != s[i-2] { ans = append(ans, c) } } diff --git a/solution/1900-1999/1957.Delete Characters to Make Fancy String/Solution.java b/solution/1900-1999/1957.Delete Characters to Make Fancy String/Solution.java index 0947382c03255..4828771d9f284 100644 --- a/solution/1900-1999/1957.Delete Characters to Make Fancy String/Solution.java +++ b/solution/1900-1999/1957.Delete Characters to Make Fancy String/Solution.java @@ -1,12 +1,12 @@ class Solution { public String makeFancyString(String s) { StringBuilder ans = new StringBuilder(); - for (char c : s.toCharArray()) { - int n = ans.length(); - if (n < 2 || c != ans.charAt(n - 1) || c != ans.charAt(n - 2)) { + for (int i = 0; i < s.length(); ++i) { + char c = s.charAt(i); + if (i < 2 || c != s.charAt(i - 1) || c != s.charAt(i - 2)) { ans.append(c); } } return ans.toString(); } -} +} \ No newline at end of file diff --git a/solution/1900-1999/1957.Delete Characters to Make Fancy String/Solution.js b/solution/1900-1999/1957.Delete Characters to Make Fancy String/Solution.js index 16bfe1a2a7c98..745e2443b1d37 100644 --- a/solution/1900-1999/1957.Delete Characters to Make Fancy String/Solution.js +++ b/solution/1900-1999/1957.Delete Characters to Make Fancy String/Solution.js @@ -1,9 +1,13 @@ -function makeFancyString(s) { - let [n, ans] = [s.length, '']; - for (let i = 0; i < n; i++) { +/** + * @param {string} s + * @return {string} + */ +var makeFancyString = function (s) { + const ans = []; + for (let i = 0; i < s.length; ++i) { if (s[i] !== s[i - 1] || s[i] !== s[i - 2]) { - ans += s[i]; + ans.push(s[i]); } } - return ans; -} + return ans.join(''); +}; diff --git a/solution/1900-1999/1957.Delete Characters to Make Fancy String/Solution.php b/solution/1900-1999/1957.Delete Characters to Make Fancy String/Solution.php index 41b56186c248a..dc20f0120a451 100644 --- a/solution/1900-1999/1957.Delete Characters to Make Fancy String/Solution.php +++ b/solution/1900-1999/1957.Delete Characters to Make Fancy String/Solution.php @@ -4,16 +4,13 @@ class Solution { * @return String */ function makeFancyString($s) { - $ans = []; - $length = strlen($s); - - for ($i = 0; $i < $length; $i++) { - $n = count($ans); - if ($n < 2 || $s[$i] !== $ans[$n - 1] || $s[$i] !== $ans[$n - 2]) { - $ans[] = $s[$i]; + $ans = ''; + for ($i = 0; $i < strlen($s); $i++) { + $c = $s[$i]; + if ($i < 2 || $c !== $s[$i - 1] || $c !== $s[$i - 2]) { + $ans .= $c; } } - - return implode('', $ans); + return $ans; } -} +} \ No newline at end of file diff --git a/solution/1900-1999/1957.Delete Characters to Make Fancy String/Solution.py b/solution/1900-1999/1957.Delete Characters to Make Fancy String/Solution.py index 76eb795267313..d601ec8b77fb2 100644 --- a/solution/1900-1999/1957.Delete Characters to Make Fancy String/Solution.py +++ b/solution/1900-1999/1957.Delete Characters to Make Fancy String/Solution.py @@ -1,7 +1,7 @@ class Solution: def makeFancyString(self, s: str) -> str: ans = [] - for c in s: - if len(ans) < 2 or ans[-1] != c or ans[-2] != c: + for i, c in enumerate(s): + if i < 2 or c != s[i - 1] or c != s[i - 2]: ans.append(c) return "".join(ans) diff --git a/solution/1900-1999/1957.Delete Characters to Make Fancy String/Solution.ts b/solution/1900-1999/1957.Delete Characters to Make Fancy String/Solution.ts index 6f86484842ea4..bc989a239c6d2 100644 --- a/solution/1900-1999/1957.Delete Characters to Make Fancy String/Solution.ts +++ b/solution/1900-1999/1957.Delete Characters to Make Fancy String/Solution.ts @@ -1,9 +1,9 @@ function makeFancyString(s: string): string { - let [n, ans] = [s.length, '']; - for (let i = 0; i < n; i++) { + const ans: string[] = []; + for (let i = 0; i < s.length; ++i) { if (s[i] !== s[i - 1] || s[i] !== s[i - 2]) { - ans += s[i]; + ans.push(s[i]); } } - return ans; + return ans.join(''); }