feat: add solutions to lc problem: No.0541.Reverse String II

Author: yanglbme

solution/0500-0599/0541.Reverse String II/README.md

@@ -42,15 +42,68 @@
 <!-- 这里可写当前语言的特殊实现逻辑 -->
 
 ```python
-
+class Solution:
+    def reverseStr(self, s: str, k: int) -> str:
+        t = list(s)
+        for i in range(0, len(t), k << 1):
+            t[i: i + k] = reversed(t[i: i + k])
+        return ''.join(t)
 ```
 
 ### **Java**
 
 <!-- 这里可写当前语言的特殊实现逻辑 -->
 
 ```java
+class Solution {
+    public String reverseStr(String s, int k) {
+        char[] chars = s.toCharArray();
+        for (int i = 0; i < chars.length; i += (k << 1)) {
+            for (int st = i, ed = Math.min(chars.length - 1, i + k - 1); st < ed; ++st, --ed) {
+                char t = chars[st];
+                chars[st] = chars[ed];
+                chars[ed] = t;
+            }
+        }
+        return new String(chars);
+    }
+}
+```
+
+### **C++**
+
+```cpp
+class Solution {
+public:
+    string reverseStr(string s, int k) {
+        for (int i = 0, n = s.size(); i < n; i += (k << 1))
+        {
+            reverse(s.begin() + i, s.begin() + min(i + k, n));
+        }
+        return s;
+    }
+};
+```
 
+### **Go**
+
+```go
+func reverseStr(s string, k int) string {
+	t := []byte(s)
+	for i := 0; i < len(t); i += (k << 1) {
+		for st, ed := i, min(i+k-1, len(t)-1); st < ed; st, ed = st+1, ed-1 {
+			t[st], t[ed] = t[ed], t[st]
+		}
+	}
+	return string(t)
+}
+
+func min(a, b int) int {
+	if a < b {
+		return a
+	}
+	return b
+}
 ```
 
 ### **...**

solution/0500-0599/0541.Reverse String II/README_EN.md

@@ -33,13 +33,66 @@
 ### **Python3**
 
 ```python
-
+class Solution:
+    def reverseStr(self, s: str, k: int) -> str:
+        t = list(s)
+        for i in range(0, len(t), k << 1):
+            t[i: i + k] = reversed(t[i: i + k])
+        return ''.join(t)
 ```
 
 ### **Java**
 
 ```java
+class Solution {
+    public String reverseStr(String s, int k) {
+        char[] chars = s.toCharArray();
+        for (int i = 0; i < chars.length; i += (k << 1)) {
+            for (int st = i, ed = Math.min(chars.length - 1, i + k - 1); st < ed; ++st, --ed) {
+                char t = chars[st];
+                chars[st] = chars[ed];
+                chars[ed] = t;
+            }
+        }
+        return new String(chars);
+    }
+}
+```
+
+### **C++**
+
+```cpp
+class Solution {
+public:
+    string reverseStr(string s, int k) {
+        for (int i = 0, n = s.size(); i < n; i += (k << 1))
+        {
+            reverse(s.begin() + i, s.begin() + min(i + k, n));
+        }
+        return s;
+    }
+};
+```
 
+### **Go**
+
+```go
+func reverseStr(s string, k int) string {
+	t := []byte(s)
+	for i := 0; i < len(t); i += (k << 1) {
+		for st, ed := i, min(i+k-1, len(t)-1); st < ed; st, ed = st+1, ed-1 {
+			t[st], t[ed] = t[ed], t[st]
+		}
+	}
+	return string(t)
+}
+
+func min(a, b int) int {
+	if a < b {
+		return a
+	}
+	return b
+}
 ```
 
 ### **...**

solution/0500-0599/0541.Reverse String II/Solution.cpp

@@ -0,0 +1,10 @@
+class Solution {
+public:
+    string reverseStr(string s, int k) {
+        for (int i = 0, n = s.size(); i < n; i += (k << 1))
+        {
+            reverse(s.begin() + i, s.begin() + min(i + k, n));
+        }
+        return s;
+    }
+};

solution/0500-0599/0541.Reverse String II/Solution.go

@@ -0,0 +1,16 @@
+func reverseStr(s string, k int) string {
+	t := []byte(s)
+	for i := 0; i < len(t); i += (k << 1) {
+		for st, ed := i, min(i+k-1, len(t)-1); st < ed; st, ed = st+1, ed-1 {
+			t[st], t[ed] = t[ed], t[st]
+		}
+	}
+	return string(t)
+}
+
+func min(a, b int) int {
+	if a < b {
+		return a
+	}
+	return b
+}

solution/0500-0599/0541.Reverse String II/Solution.java

@@ -1,26 +1,13 @@
 class Solution {
     public String reverseStr(String s, int k) {
-        if (k < 2) return s;
-        StringBuilder sb = new StringBuilder();
-        int length = s.length(), index = 0;
-        while (index < length) {
-            if (index + 2 * k <= length) {
-                sb.append(reverse(s, index, index + k));
-                sb.append(s.substring(index + k, index + 2 * k));
-                index += 2 * k;
-            } else if (index + k <= length){
-                sb.append(reverse(s, index, index + k));
-                sb.append(s.substring(index + k));
-                break;
-            } else {
-                sb.append(reverse(s, index, length));
-                break;
+        char[] chars = s.toCharArray();
+        for (int i = 0; i < chars.length; i += (k << 1)) {
+            for (int st = i, ed = Math.min(chars.length - 1, i + k - 1); st < ed; ++st, --ed) {
+                char t = chars[st];
+                chars[st] = chars[ed];
+                chars[ed] = t;
             }
         }
-        return sb.toString();
-    }
-
-    private StringBuffer reverse(String s, int index, int end) {
-        return new StringBuffer(s.substring(index, end)).reverse();
+        return new String(chars);
     }
 }

solution/0500-0599/0541.Reverse String II/Solution.py

@@ -0,0 +1,6 @@
+class Solution:
+    def reverseStr(self, s: str, k: int) -> str:
+        t = list(s)
+        for i in range(0, len(t), k << 1):
+            t[i: i + k] = reversed(t[i: i + k])
+        return ''.join(t)