leetcode--最长公共前缀（比较难理解）

https://leetcode-cn.com/problems/longest-common-prefix/solution/zui-chang-gong-gong-qian-zhui-by-leetcode-solution/

https://leetcode-cn.com/problems/longest-common-prefix/solution/hua-jie-suan-fa-14-zui-chang-gong-gong-qian-zhui-b/

1. 横向比较

2. 纵向比较

3. 分治法

4. 二分查找