[1、给个二维数组，输出其中个位为9的数量](1%E3%80%81%E7%BB%99%E4%B8%AA%E4%BA%8C%E7%BB%B4%E6%95%B0%E7%BB%84%EF%BC%8C%E8%BE%93%E5%87%BA%E5%85%B6%E4%B8%AD%E4%B8%AA%E4%BD%8D%E4%B8%BA9%E7%9A%84%E6%95%B0%E9%87%8F.md) [2、爬楼题，每次爬一个，或者爬两个，问最小花费](2%E3%80%81%E7%88%AC%E6%A5%BC%E9%A2%98%EF%BC%8C%E6%AF%8F%E6%AC%A1%E7%88%AC%E4%B8%80%E4%B8%AA%EF%BC%8C%E6%88%96%E8%80%85%E7%88%AC%E4%B8%A4%E4%B8%AA%EF%BC%8C%E9%97%AE%E6%9C%80%E5%B0%8F%E8%8A%B1%E8%B4%B9.md) [3、对给定数值求所有子数组权重和](3%E3%80%81%E5%AF%B9%E7%BB%99%E5%AE%9A%E6%95%B0%E5%80%BC%E6%B1%82%E6%89%80%E6%9C%89%E5%AD%90%E6%95%B0%E7%BB%84%E6%9D%83%E9%87%8D%E5%92%8C.md)