[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".

注意考虑有多个空格的情况就好了，选择的处理办法是在进行空格查找之前先整理字符串

#include <string>
#include <algorithm>
using namespace std;
class Solution {
public:
    void reverseWords(string &s) {
        checkString(s);
        size_t found;
        string str;
        found = s.find_last_of(" ");
        while(found != string::npos){
            str += s.substr(found+1) + " ";
            s = s.substr(0,found);
            found = s.find_last_of(" ");
        }
        str+=s;
        s = str;
    }
    void checkString(string &s){
        while(s[0] == ' ') s.erase(0,1);
        if(s.size() == 0)    return;
        while(s[s.size()-1] == ' ') s.erase(s.size()-1);
        for(int i = 0; i < s.size()-1;i++){
            if(s[i] == ' ' && s[i+1] == ' ') {
                s.erase(i--,1);
            }
        }
        return ;
    }
};