recursive filtering

例句：

1. 1. The algorithm is designed to be recursive and easy to understand.
   这个算法被设计为递归的，易于理解。
2. 2. The process of recursion is a way to solve complex problems by breaking them down into simpler subproblems.
   递归过程是一种将复杂问题分解成更简单子问题的方法。
3. 3. The recursive function calls itself with different arguments until it reaches a base case.
   递归函数使用不同的参数调用自身，直到达到基线情况。