leetcode刷题笔记(python3)--151. Reverse Words in a String

151. Reverse Words in a String

Given an input string, reverse the string word by word.

Example 1:

Input: “the sky is blue”
Output: “blue is sky the”
Example 2:

Input: " hello world! "
Output: “world! hello”
Explanation: Your reversed string should not contain leading or trailing spaces.
Example 3:

Input: “a good example”
Output: “example good a”
Explanation: You need to reduce multiple spaces between two words to a single space in the reversed string.

Note:

A word is defined as a sequence of non-space characters.
Input string may contain leading or trailing spaces. However, your reversed string should not contain leading or trailing spaces.
You need to reduce multiple spaces between two words to a single space in the reversed string.
不是很清楚为什么golang的strings.Split()函数会分割出空字符串

func reverseWords(s string) string {
	res := []string{}
	sReverse := reverseString(s)
	words := strings.Split(sReverse, " ")
	for _, v := range words {
		if v ==""{
			continue
		}
		res = append(res, reverseString(v))
	}
	return strings.Join(res, " ")
}

func reverseString(s string) string {
	runes := []rune(s)
	for from, to := 0, len(runes)-1; from < to; from, to = from+1, to-1 {
		runes[from], runes[to] = runes[to], runes[from]
	}
	return string(runes)
}