Reverse Words in a String

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本文探讨了如何通过编程实现输入字符串中单词级别的反转。详细解释了如何处理字符串中的空格，确保反转后的字符串中单词顺序正确且无多余空格。

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

For example,
Given s = "the sky is blue",
return "blue is sky the".

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.

class Solution {
public:
    void reverseWords(string &s)
	{
        string res;
		size_t found1 = 0;
		while(1)
		{
			found1 = s.find_first_not_of(' ', found1);
			if (found1 == string::npos)
				break;
			size_t found2 = s.find_first_of(' ', found1);
			if (!res.empty())
				res = ' ' + res;
			if (found2 == string::npos)
			{
				res  = s.substr(found1) + res;
				break;
			}
			res  = s.substr(found1, found2 - found1) + res;
			found1 = found2;
		}
		 s = res;
    }
};