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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".

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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.
思路:从头往后扫描字符串,从第一个开始不是空格算起。将单词放入temp中,直到遇到空格,作如下处理,将单词放入result中去,接下来再有单词可以放到上一个单词的前面,另加空格。如此反复,就可以将单词与单词为单位反转了。
class Solution {public:    void reverseWords(string &s) {        int nLen=s.size();        if(nLen<=0)            return;        string temp,result;        int index=0;        while(s[index]== )            index++;        for(int i=index;i<nLen;)        {            if(s[i]!= )            {                temp+=s[i];                i++;            }            else            {                while(s[i]== )                    i++;                if(i==nLen)                    break;                result=" "+temp+result;                temp="";            }        }        s=temp+result;    }};