reverseWords.go

/* https://leetcode.com/problems/reverse-words-in-a-string-iii/#/description
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.
*/

package lstring

func reverseWords(s string) string {
	sList := []byte(s)

	reverse := func(sList []byte, start, end int) {
		for i := 0; i < (end-start)/2; i++ {
			sList[start+i], sList[end-1-i] = sList[end-1-i], sList[start+i]
		}
	}

	start, end := 0, 0
	for ; end < len(sList); end++ {
		if sList[end] == ' ' {
			reverse(sList, start, end)
			start = end + 1
		}
	}
	reverse(sList, start, end)

	return string(sList)
}