fix: java code

Author: yanglbme

solution/0200-0299/0214.Shortest Palindrome/README.md

@@ -271,8 +271,9 @@ class Solution:
 ```java
 class Solution {
     public String shortestPalindrome(String s) {
-        char[] t = (s + "#" + new StringBuilder(s).reverse().toString() + "$").toCharArray();
-        int n = t.length();
+        String rev = new StringBuilder(s).reverse().toString();
+        char[] t = (s + "#" + rev + "$").toCharArray();
+        int n = t.length;
         int[] next = new int[n];
         next[0] = -1;
         for (int i = 2, j = 0; i < n;) {
@@ -284,7 +285,7 @@ class Solution {
                 next[i++] = 0;
             }
         }
-        return new StringBuilder(s.substring(next[n - 1])).reverse().substring(0, s.length() - next[n - 1]) + s;
+        return rev.substring(0, s.length() - next[n - 1]) + s;
     }
 }
 ```

solution/0200-0299/0214.Shortest Palindrome/README_EN.md

@@ -252,8 +252,9 @@ class Solution:
 ```java
 class Solution {
     public String shortestPalindrome(String s) {
-        char[] t = (s + "#" + new StringBuilder(s).reverse().toString() + "$").toCharArray();
-        int n = t.length();
+        String rev = new StringBuilder(s).reverse().toString();
+        char[] t = (s + "#" + rev + "$").toCharArray();
+        int n = t.length;
         int[] next = new int[n];
         next[0] = -1;
         for (int i = 2, j = 0; i < n;) {
@@ -265,7 +266,7 @@ class Solution {
                 next[i++] = 0;
             }
         }
-        return new StringBuilder(s.substring(next[n - 1])).reverse().substring(0, s.length() - next[n - 1]) + s;
+        return rev.substring(0, s.length() - next[n - 1]) + s;
     }
 }
 ```

solution/0200-0299/0214.Shortest Palindrome/Solution2.java

@@ -1,7 +1,8 @@
 class Solution {
     public String shortestPalindrome(String s) {
-        char[] t = (s + "#" + new StringBuilder(s).reverse().toString() + "$").toCharArray();
-        int n = t.length();
+        String rev = new StringBuilder(s).reverse().toString();
+        char[] t = (s + "#" + rev + "$").toCharArray();
+        int n = t.length;
         int[] next = new int[n];
         next[0] = -1;
         for (int i = 2, j = 0; i < n;) {
@@ -13,6 +14,6 @@ public String shortestPalindrome(String s) {
                 next[i++] = 0;
             }
         }
-        return new StringBuilder(s.substring(next[n - 1])).reverse().substring(0, s.length() - next[n - 1]) + s;
+        return rev.substring(0, s.length() - next[n - 1]) + s;
     }
 }