寻找最长回文子串

题目

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.

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class Palindrome
{
    public static string FindLongestSubPalindromeStr(string sourceStr)
    {
        string dstStr = "";
        if(sourceStr.Length == 0)
            return dstStr;

        for(int centerIndex = 0; centerIndex<sourceStr.Length; centerIndex++)
        {
            string curStr = sourceStr[centerIndex].ToString();
            int left = centerIndex - 1;
            int right = centerIndex + 1;
            //判断奇数
            while(left>=0 && right<sourceStr.Length)
            {
                if(sourceStr[left] != sourceStr[right])
                    break;
                else
                {
                    curStr = sourceStr.SubString(left, right-left+1);
                    left--;
                    right++;
                }
            }

            if(curStr.Length > dstStr.Length)
            {
                dstStr = curStr;
            }

            //判断偶数
            int middleRight = centerIndex + 1;

            if(middleRight >=sourceStr.Length)
                continue;
            if(sourceStr[centerIndex] != sourceStr[middleRight])
                continue;

            left = centerIndex - 1;
            right = middleRight + 1;
            while(left>=0 && right<sourceStr.Length)
            {
                if(sourceStr[left] != sourceStr[right])
                    break;
                else
                {
                    curStr = sourceStr.SubString(left, right-left+1);
                    left--;
                    right++;
                }
            }

            if(curStr.Length > dstStr.Length)
            {
                dstStr = curStr;
            }
        }
        return dstStr;
    }
}