[1、长度为n的数组，陡峭值是相邻两数差的绝对值之和，求只修改第i个元素，让f（i）最小的各个陡峭值](1%E3%80%81%E9%95%BF%E5%BA%A6%E4%B8%BAn%E7%9A%84%E6%95%B0%E7%BB%84%EF%BC%8C%E9%99%A1%E5%B3%AD%E5%80%BC%E6%98%AF%E7%9B%B8%E9%82%BB%E4%B8%A4%E6%95%B0%E5%B7%AE%E7%9A%84%E7%BB%9D%E5%AF%B9%E5%80%BC%E4%B9%8B%E5%92%8C%EF%BC%8C%E6%B1%82%E5%8F%AA%E4%BF%AE%E6%94%B9%E7%AC%ACi%E4%B8%AA%E5%85%83%E7%B4%A0%EF%BC%8C%E8%AE%A9f%EF%BC%88i%EF%BC%89%E6%9C%80%E5%B0%8F%E7%9A%84%E5%90%84%E4%B8%AA%E9%99%A1%E5%B3%AD%E5%80%BC.md) [2、字符串构造，每个小写字母都要出现至少两次，而且相同字母的最小距离刚好是k](2%E3%80%81%E5%AD%97%E7%AC%A6%E4%B8%B2%E6%9E%84%E9%80%A0%EF%BC%8C%E6%AF%8F%E4%B8%AA%E5%B0%8F%E5%86%99%E5%AD%97%E6%AF%8D%E9%83%BD%E8%A6%81%E5%87%BA%E7%8E%B0%E8%87%B3%E5%B0%91%E4%B8%A4%E6%AC%A1%EF%BC%8C%E8%80%8C%E4%B8%94%E7%9B%B8%E5%90%8C%E5%AD%97%E6%AF%8D%E7%9A%84%E6%9C%80%E5%B0%8F%E8%B7%9D%E7%A6%BB%E5%88%9A%E5%A5%BD%E6%98%AFk.md)