[1、判断一个字符串中长度为K的伪回文串的个数](1%E3%80%81%E5%88%A4%E6%96%AD%E4%B8%80%E4%B8%AA%E5%AD%97%E7%AC%A6%E4%B8%B2%E4%B8%AD%E9%95%BF%E5%BA%A6%E4%B8%BAK%E7%9A%84%E4%BC%AA%E5%9B%9E%E6%96%87%E4%B8%B2%E7%9A%84%E4%B8%AA%E6%95%B0.md) [2、求字符串的极值](2%E3%80%81%E6%B1%82%E5%AD%97%E7%AC%A6%E4%B8%B2%E7%9A%84%E6%9E%81%E5%80%BC.md) [3、求长度为k的伪回文子串的数量](3%E3%80%81%E6%B1%82%E9%95%BF%E5%BA%A6%E4%B8%BAk%E7%9A%84%E4%BC%AA%E5%9B%9E%E6%96%87%E5%AD%90%E4%B8%B2%E7%9A%84%E6%95%B0%E9%87%8F.md)