Given a string, you need to reverse the order of characters in each word within a sentence while still preserving whitespace and initial word order.

Example 1:

Input: "Let's take LeetCode contest" Output: "s'teL ekat edoCteeL tsetnoc" 

Note: In the string, each word is separated by single space and there will not be any extra space in the string.

给定一个字符串，你需要反转字符串中每个单词的字符顺序，同时仍保留空格和单词的初始顺序。注意：在字符串中，每个单词由单个空格分隔，并且字符串中不会有任何额外的空格。

• 反转字符串，要求按照空格隔开的小字符串为单位反转。
• 这是一道简单题。按照题意反转每个空格隔开的单词即可。