Recursion

Abstract

---

• 3 components
  1. Starting point: break down the big problem, and sum up the answers of sub-problems, and return it as final answer
  2. Progression: obtaining the answers of sub-problems
  3. Base case: the terminating point of recursion
• 递归解题思路主要还是聚焦在一个节点，想想在这一个节点上要做点啥，递归就像‘水波纹’把这‘做点啥’传递到其它节点上