LeetCode OJ-- Reverse Words in a String

https://oj.leetcode.com/problems/reverse-words-in-a-string/

给一个字符串 abc dd m,返回 m dd abc.

注意：输入中可能有前置或者后置空格，要求，都删除掉。输出的每个单词之间，空格大小为1.

class Solution {

public:

    void reverseWords(string &s) {

        if(s.empty())

            return;

        //remove heading and trailing spaces

        int i = ;

        while(i<s.size() && s[i] == ' ')

            i++;

        if(i == s.size())

        {

            s = "";

            return;

        }

        int j = s.size() - ;

        while(j>- && s[j] == ' ')

            j--;

        if(j == -)

        {

            s = "";

            return;

        }

        s = s.substr(i,j - i + );

        size_t pos = ;

        vector<string> strs;

        size_t begin = ;

        while(begin < s.size())

        {

            pos = s.find_first_of(' ',begin);

            if(pos == begin)

            {

                begin++;

                continue;

            }

            else if(pos != -)

                strs.push_back(s.substr(begin,pos - begin));

            else  //pos == -1, the end

            {

                strs.push_back(s.substr(begin,s.size() -  - begin + ));

                break;

            }

            begin = pos + ;

        }

        string ans;

        for(int i = strs.size() - ; i > ; i--)

        {

            ans += strs[i];

            ans += " ";

        }

        ans += strs[];

        s = ans;

    }

};

巴特西

LeetCode OJ-- Reverse Words in a String

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