leetcode string reverse word order column

THE

problem

solution

Code

//不知不觉刷到42题了，这道题主要思想就是先翻转所有字符，再逐个单词翻转，逐个单词翻转的时候考虑三种不同情况即可。
class Solution {
    
    
public:
   void Reverse(string& sent, int begin, int end)
{
    
    
   if (begin<0 || end<0)
       return;
   while (begin<end)
   {
    
    
       char c;
       c = sent[begin];
       sent[begin] = sent[end];
       sent[end] = c;
       begin++;
       end--;

   }
}
string ReverseSentence( string &str) {
    
    
   int length = str.size();

   if (length <= 1)
       return str;
   int pBegin = 0;
   int pEnd = 0;
   while (str[pEnd] != '\0')
   {
    
    
       pEnd++;
   }
   pEnd--;
   Reverse(str, pBegin, pEnd);

   pBegin = pEnd = 0;
   while (str[pBegin] != '\0')
   {
    
    
       if (str[pBegin] == ' ')
       {
    
    
           pBegin++;
           pEnd++;
       }
       else if (str[pEnd] == ' ' || str[pEnd] == '\0')
       {
    
    
           Reverse(str, pBegin, --pEnd);
           pBegin = ++pEnd;
       }
       else
       {
    
    
           pEnd++;
       }
   }
   return str;
}

};

Summary and reflection

1. This hard topic has too many details. It belongs to the most difficult problem in the simple string problem. No ac comes out. Copy the answer.