151. Reverse Words in a String

Solution idea

Two Pointers

• Step 1: remove leading spaces, trailing spaces, and extra spaces betweeen words

  • Implementation 是 27. Remove Element 的进阶版

• Step 2a: reverse all characters all at once. 一整个字符串翻转

• Step 2b: reverse all chars per word. 每个词每个词单独翻转

Time complexity = $O(n^2)$

Resource

代码随想录-151.翻转字符串里的单词