refactor: remove Java code sections from all LeetCode Hot 100 markdown files

- Remove all "## Java 解法" sections and Java code blocks
- Replace "## Go 解法" with "## 解法"
- Remove "### Go 代码要点" and "### Java 代码要点" sections
- Keep all Go code sections intact
- Maintain complete documentation structure and content
- Update 22 markdown files in the LeetCode Hot 100 directory

16-LeetCode Hot 100/最长回文子串.md

@@ -136,71 +136,6 @@ func main() {
 
 ### Java 实现（中心扩展法）
 
-```java
-public class LongestPalindromicSubstring {
-
-    public String longestPalindrome(String s) {
-        if (s == null || s.length() < 2) {
-            return s;
-        }
-
-        int start = 0, maxLen = 1;
-
-        for (int i = 0; i < s.length(); i++) {
-            // 奇数长度：以当前字符为中心
-            int len1 = expandAroundCenter(s, i, i);
-            // 偶数长度：以当前字符和下一个字符之间为中心
-            int len2 = expandAroundCenter(s, i, i + 1);
-
-            int currentLen = Math.max(len1, len2);
-            if (currentLen > maxLen) {
-                maxLen = currentLen;
-                start = i - (currentLen - 1) / 2;
-            }
-        }
-
-        return s.substring(start, start + maxLen);
-    }
-
-    private int expandAroundCenter(String s, int left, int right) {
-        while (left >= 0 && right < s.length() && s.charAt(left) == s.charAt(right)) {
-            left--;
-            right++;
-        }
-        return right - left - 1;
-    }
-
-    // 测试用例
-    public static void main(String[] args) {
-        LongestPalindromicSubstring solution = new LongestPalindromicSubstring();
-
-        // 测试用例1
-        String s1 = "babad";
-        System.out.println("输入: " + s1);
-        System.out.println("输出: " + solution.longestPalindrome(s1));
-
-        // 测试用例2
-        String s2 = "cbbd";
-        System.out.println("\n输入: " + s2);
-        System.out.println("输出: " + solution.longestPalindrome(s2));
-
-        // 测试用例3: 单个字符
-        String s3 = "a";
-        System.out.println("\n输入: " + s3);
-        System.out.println("输出: " + solution.longestPalindrome(s3));
-
-        // 测试用例4: 全部相同
-        String s4 = "aaaa";
-        System.out.println("\n输入: " + s4);
-        System.out.println("输出: " + solution.longestPalindrome(s4));
-
-        // 测试用例5: 无回文
-        String s5 = "abc";
-        System.out.println("\n输入: " + s5);
-        System.out.println("输出: " + solution.longestPalindrome(s5));
-    }
-}
-```
 
 ### Go 实现（动态规划）
 
@@ -246,41 +181,6 @@ func longestPalindromeDP(s string) string {
 
 ### Java 实现（动态规划）
 
-```java
-public String longestPalindromeDP(String s) {
-    if (s == null || s.length() < 2) {
-        return s;
-    }
-
-    int n = s.length();
-    boolean[][] dp = new boolean[n][n];
-    int start = 0, maxLen = 1;
-
-    // 初始化：所有单个字符都是回文串
-    for (int i = 0; i < n; i++) {
-        dp[i][i] = true;
-    }
-
-    // 按长度递增的顺序遍历
-    for (int length = 2; length <= n; length++) {
-        for (int i = 0; i <= n - length; i++) {
-            int j = i + length - 1;
-
-            if (s.charAt(i) == s.charAt(j)) {
-                if (length == 2 || dp[i + 1][j - 1]) {
-                    dp[i][j] = true;
-                    if (length > maxLen) {
-                        maxLen = length;
-                        start = i;
-                    }
-                }
-            }
-        }
-    }
-
-    return s.substring(start, start + maxLen);
-}
-```
 
 ### Go 实现（Manacher 算法）