From c14d9f3154db24b3903e94fccfb685cec133dc2d Mon Sep 17 00:00:00 2001
From: zeekling <lingzhaohui@zeekling.cn>
Date: Sun, 15 Nov 2020 23:12:52 +0800
Subject: [PATCH] =?UTF-8?q?=E6=9C=80=E9=95=BF=E5=9B=9E=E6=96=87=E5=AD=90?=
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---
 .../leetcode/string/LongestPalindrome.java    | 61 +++++++++++++++++++
 1 file changed, 61 insertions(+)
 create mode 100644 src/main/java/com/leetcode/string/LongestPalindrome.java

diff --git a/src/main/java/com/leetcode/string/LongestPalindrome.java b/src/main/java/com/leetcode/string/LongestPalindrome.java
new file mode 100644
index 0000000..b047df3
--- /dev/null
+++ b/src/main/java/com/leetcode/string/LongestPalindrome.java
@@ -0,0 +1,61 @@
+package com.leetcode.string;
+
+/**
+ * 
+ 最长回文子串:
+ 给定一个字符串 s，找到 s 中最长的回文子串。你可以假设 s 的最大长度为 1000。
+
+示例 1：
+
+输入: "babad"
+输出: "bab"
+注意: "aba" 也是一个有效答案。
+示例 2：
+
+输入: "cbbd"
+输出: "bb"
+
+来源：力扣（LeetCode）
+链接：https://leetcode-cn.com/problems/longest-palindromic-substring
+著作权归领扣网络所有。商业转载请联系官方授权，非商业转载请注明出处。
+ 
+ * @author zeek
+ *
+ */
+public class LongestPalindrome {
+
+	
+	public String longestPalindrome(String s) {
+		if (s == null || s.length() < 1) {
+            return "";
+        }
+        int start = 0, end = 0;
+        for (int i = 0; i < s.length(); i++) {
+            int len1 = expandAroundCenter(s, i, i);
+            int len2 = expandAroundCenter(s, i, i + 1);
+            int len = Math.max(len1, len2);
+            if (len > end - start) {
+                start = i - (len - 1) / 2;
+                end = i + len / 2;
+            }
+        }
+        return s.substring(start, end + 1);
+
+    }
+	
+	public 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;
+    }
+
+	
+	public static void main(String[] args) {
+		LongestPalindrome rome = new LongestPalindrome();
+		String s = "cbbd";
+		String res = rome.longestPalindrome(s);
+		System.out.println(res);
+	}
+}