Leetcode Reverse Words in a String

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

For example,
Given s = "

the sky is blue

",
return "

blue is sky the

".

解题思路：

用trim() 和splite("\\s+")把String 切割成一个一个word, 然后用StringBuilder 重建String. O(n) time and O(n) Space

Java code:

public String reverseWords(String s) {
if( s == null || s.length() == 0 ){
return "";
}
String[] splited = s.trim().split("\\s+");
int len = splited.length;
StringBuilder sb = new StringBuilder();
for(int i = len-1; i >= 0; i--){
sb.append(splited[i] + " ");
}
return sb.toString().trim();
}

Reference:

1. https://leetcode.com/discuss/56712/straightforward-java-solution-using-split