[1、做题：字符串，每次只能删含有相同元素的连续子串，最少删多少次能删成空串](1%E3%80%81%E5%81%9A%E9%A2%98%EF%BC%9A%E5%AD%97%E7%AC%A6%E4%B8%B2%EF%BC%8C%E6%AF%8F%E6%AC%A1%E5%8F%AA%E8%83%BD%E5%88%A0%E5%90%AB%E6%9C%89%E7%9B%B8%E5%90%8C%E5%85%83%E7%B4%A0%E7%9A%84%E8%BF%9E%E7%BB%AD%E5%AD%90%E4%B8%B2%EF%BC%8C%E6%9C%80%E5%B0%91%E5%88%A0%E5%A4%9A%E5%B0%91%E6%AC%A1%E8%83%BD%E5%88%A0%E6%88%90%E7%A9%BA%E4%B8%B2.md) [2、给两个字符串，可以修改第一个字符串的一个字符（只能修改第一个字符串，第二个不可以改），求两个字符串的相同前缀数和相同后缀数乘积](2%E3%80%81%E7%BB%99%E4%B8%A4%E4%B8%AA%E5%AD%97%E7%AC%A6%E4%B8%B2%EF%BC%8C%E5%8F%AF%E4%BB%A5%E4%BF%AE%E6%94%B9%E7%AC%AC%E4%B8%80%E4%B8%AA%E5%AD%97%E7%AC%A6%E4%B8%B2%E7%9A%84%E4%B8%80%E4%B8%AA%E5%AD%97%E7%AC%A6%EF%BC%88%E5%8F%AA%E8%83%BD%E4%BF%AE%E6%94%B9%E7%AC%AC%E4%B8%80%E4%B8%AA%E5%AD%97%E7%AC%A6%E4%B8%B2%EF%BC%8C%E7%AC%AC%E4%BA%8C%E4%B8%AA%E4%B8%8D%E5%8F%AF%E4%BB%A5%E6%94%B9%EF%BC%89%EF%BC%8C%E6%B1%82%E4%B8%A4%E4%B8%AA%E5%AD%97%E7%AC%A6%E4%B8%B2%E7%9A%84%E7%9B%B8%E5%90%8C%E5%89%8D%E7%BC%80%E6%95%B0%E5%92%8C%E7%9B%B8%E5%90%8C%E5%90%8E%E7%BC%80%E6%95%B0%E4%B9%98%E7%A7%AF.md)