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 3092d6b382469..5811b0e2fbf46 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
@@ -70,7 +70,13 @@ tags:
<!-- solution:start -->
-### 方法一
+### 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。
+
+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。
<!-- tabs:start -->
@@ -81,10 +87,9 @@ class Solution:
def makeFancyString(self, s: str) -> str:
ans = []
for c in s:
- if len(ans) > 1 and ans[-1] == ans[-2] == c:
- continue
- ans.append(c)
- return ''.join(ans)
+ if len(ans) < 2 or ans[-1] != c or ans[-2] != c:
+ ans.append(c)
+ return "".join(ans)
```
#### Java
@@ -95,10 +100,9 @@ class Solution {
StringBuilder ans = new StringBuilder();
for (char c : s.toCharArray()) {
int n = ans.length();
- if (n > 1 && ans.charAt(n - 1) == c && ans.charAt(n - 2) == c) {
- continue;
+ if (n < 2 || c != ans.charAt(n - 1) || c != ans.charAt(n - 2)) {
+ ans.append(c);
}
- ans.append(c);
}
return ans.toString();
}
@@ -114,8 +118,9 @@ public:
string ans = "";
for (char& c : s) {
int n = ans.size();
- if (n > 1 && ans[n - 1] == c && ans[n - 2] == c) continue;
- ans.push_back(c);
+ if (n < 2 || ans[n - 1] != c || ans[n - 2] != c) {
+ ans += c;
+ }
}
return ans;
}
@@ -128,16 +133,29 @@ public:
func makeFancyString(s string) string {
ans := []rune{}
for _, c := range s {
- n := len(ans)
- if n > 1 && ans[n-1] == c && ans[n-2] == c {
- continue
+ if n := len(ans); n < 2 || c != ans[n-1] || c != ans[n-2] {
+ ans = append(ans, c)
}
- ans = append(ans, c)
}
return string(ans)
}
```
+#### TypeScript
+
+```ts
+function makeFancyString(s: string): string {
+ const ans: string[] = [];
+ for (const c of s) {
+ const n = ans.length;
+ if (n < 2 || c !== ans[n - 1] || c !== ans[n - 2]) {
+ ans.push(c);
+ }
+ }
+ return ans.join('');
+}
+```
+
#### PHP
```php
@@ -147,15 +165,17 @@ class Solution {
* @return String
*/
function makeFancyString($s) {
- $rs = '';
- for ($i = 0; $i < strlen($s); $i++) {
- if ($s[$i] == $s[$i + 1] && $s[$i] == $s[$i + 2]) {
- continue;
- } else {
- $rs .= $s[$i];
+ $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];
}
}
- return $rs;
+
+ return implode('', $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 ab45eafdca3d7..074212e7ac5ec 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
@@ -68,7 +68,13 @@ No three consecutive characters are equal, so return "aabaa".
<!-- solution:start -->
-### Solution 1
+### 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 $\textit{ans}$.
+
+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 $s$.
<!-- tabs:start -->
@@ -79,10 +85,9 @@ class Solution:
def makeFancyString(self, s: str) -> str:
ans = []
for c in s:
- if len(ans) > 1 and ans[-1] == ans[-2] == c:
- continue
- ans.append(c)
- return ''.join(ans)
+ if len(ans) < 2 or ans[-1] != c or ans[-2] != c:
+ ans.append(c)
+ return "".join(ans)
```
#### Java
@@ -93,10 +98,9 @@ class Solution {
StringBuilder ans = new StringBuilder();
for (char c : s.toCharArray()) {
int n = ans.length();
- if (n > 1 && ans.charAt(n - 1) == c && ans.charAt(n - 2) == c) {
- continue;
+ if (n < 2 || c != ans.charAt(n - 1) || c != ans.charAt(n - 2)) {
+ ans.append(c);
}
- ans.append(c);
}
return ans.toString();
}
@@ -112,8 +116,9 @@ public:
string ans = "";
for (char& c : s) {
int n = ans.size();
- if (n > 1 && ans[n - 1] == c && ans[n - 2] == c) continue;
- ans.push_back(c);
+ if (n < 2 || ans[n - 1] != c || ans[n - 2] != c) {
+ ans += c;
+ }
}
return ans;
}
@@ -126,16 +131,29 @@ public:
func makeFancyString(s string) string {
ans := []rune{}
for _, c := range s {
- n := len(ans)
- if n > 1 && ans[n-1] == c && ans[n-2] == c {
- continue
+ if n := len(ans); n < 2 || c != ans[n-1] || c != ans[n-2] {
+ ans = append(ans, c)
}
- ans = append(ans, c)
}
return string(ans)
}
```
+#### TypeScript
+
+```ts
+function makeFancyString(s: string): string {
+ const ans: string[] = [];
+ for (const c of s) {
+ const n = ans.length;
+ if (n < 2 || c !== ans[n - 1] || c !== ans[n - 2]) {
+ ans.push(c);
+ }
+ }
+ return ans.join('');
+}
+```
+
#### PHP
```php
@@ -145,15 +163,17 @@ class Solution {
* @return String
*/
function makeFancyString($s) {
- $rs = '';
- for ($i = 0; $i < strlen($s); $i++) {
- if ($s[$i] == $s[$i + 1] && $s[$i] == $s[$i + 2]) {
- continue;
- } else {
- $rs .= $s[$i];
+ $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];
}
}
- return $rs;
+
+ return implode('', $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 50ea680f32aec..79416b151e375 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
@@ -4,9 +4,10 @@ class Solution {
string ans = "";
for (char& c : s) {
int n = ans.size();
- if (n > 1 && ans[n - 1] == c && ans[n - 2] == c) continue;
- ans.push_back(c);
+ if (n < 2 || ans[n - 1] != c || ans[n - 2] != c) {
+ ans += c;
+ }
}
return ans;
}
-};
\ No newline at end of file
+};
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 2d0923dd4d33c..b472925d7fd9e 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
@@ -1,11 +1,9 @@
func makeFancyString(s string) string {
ans := []rune{}
for _, c := range s {
- n := len(ans)
- if n > 1 && ans[n-1] == c && ans[n-2] == c {
- continue
+ if n := len(ans); n < 2 || c != ans[n-1] || c != ans[n-2] {
+ ans = append(ans, c)
}
- ans = append(ans, c)
}
return string(ans)
-}
\ No newline at end of file
+}
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 b456f7b5834e6..0947382c03255 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
@@ -3,11 +3,10 @@ public String makeFancyString(String s) {
StringBuilder ans = new StringBuilder();
for (char c : s.toCharArray()) {
int n = ans.length();
- if (n > 1 && ans.charAt(n - 1) == c && ans.charAt(n - 2) == c) {
- continue;
+ if (n < 2 || c != ans.charAt(n - 1) || c != ans.charAt(n - 2)) {
+ ans.append(c);
}
- 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.php b/solution/1900-1999/1957.Delete Characters to Make Fancy String/Solution.php
index ad55dfce7a289..41b56186c248a 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
@@ -4,14 +4,16 @@ class Solution {
* @return String
*/
function makeFancyString($s) {
- $rs = '';
- for ($i = 0; $i < strlen($s); $i++) {
- if ($s[$i] == $s[$i + 1] && $s[$i] == $s[$i + 2]) {
- continue;
- } else {
- $rs .= $s[$i];
+ $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];
}
}
- return $rs;
+
+ return implode('', $ans);
}
}
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 13200f885b1c2..76eb795267313 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
@@ -2,7 +2,6 @@ class Solution:
def makeFancyString(self, s: str) -> str:
ans = []
for c in s:
- if len(ans) > 1 and ans[-1] == ans[-2] == c:
- continue
- ans.append(c)
- return ''.join(ans)
+ if len(ans) < 2 or ans[-1] != c or ans[-2] != c:
+ 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
new file mode 100644
index 0000000000000..8a5edf3b949c9
--- /dev/null
+++ b/solution/1900-1999/1957.Delete Characters to Make Fancy String/Solution.ts
@@ -0,0 +1,10 @@
+function makeFancyString(s: string): string {
+ const ans: string[] = [];
+ for (const c of s) {
+ const n = ans.length;
+ if (n < 2 || c !== ans[n - 1] || c !== ans[n - 2]) {
+ ans.push(c);
+ }
+ }
+ return ans.join('');
+}