[leetcode]151. 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".Update (2015-02-12):For C programmers: Try to solve it in-place in O(1) space.click to show clarification.Clarification:    What constitutes a word?    A sequence of non-space characters constitutes a word.    Could the input string contain leading or trailing spaces?    Yes. However, your reversed string should not contain leading or trailing spaces.    How about multiple spaces between two words?    Reduce them to a single space in the reversed string.

结题思路：
由于题目中提示，输入的字符串中可能能多空格，连续空格，前缀空格，后缀空格，所以，可以将原数据去掉多个空格，成为一种字符串和单空格相连的字符串，然后再用“ ”去截取字符串，获取每个单词，然后倒序输出每个字符串到一个StringBuilder里面。最后将结果转成字符串输出。代码如下：

public class Solution {     public String reverseWords(String s) {        //处理输入数据用的StringBuilder         StringBuilder arrangeBuilder = new StringBuilder();        //盛放结果用的StringBuilder         StringBuilder resultBuilder = new StringBuilder();        //处理数据，清除多连续空格，前缀，后缀空格        for(String input:s.split(" "))        {            if (!input.isEmpty()) {                arrangeBuilder.append(input).append(" ");            }        }        //获取有效字符串        String[] temp = arrangeBuilder.toString().split(" ");        //逆向输出字符串到一个结果StringBuilder中        for (int i = temp.length-1; i >= 0; --i) {            resultBuilder.append(temp[i]).append(" ");        }        //输出结果        return resultBuilder.toString().trim();    }}