转置字符串，其中单词内的字符需要正常

如题：转置一个字符串，需要其中的单词正常

例如：

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

需要说明的是：

1、输入字符串可能会出现：前导空格，后置空格，要求输出的不能有前导空格和后置空格。

2、输入的语句中可能有两个单词之间出现多个空格，输出两个单词之间只能由一个空格。

#include <iostream>
#include <string>
using namespace std;

void reverse(string &s,int start,int end)
{
    while (start<end)
    {
        char tem = s[start];
        s[start] = s[end];
        s[end] = tem;
        start++;
        end--;
    }
}

void reverseString(string &s)
{
    if (s.empty()||s.length()==0)
    {
        return;
    }
    //去除前置和后置空格
    int num1 = s.find_first_not_of(" ");
    if (num1 == -1){
        s = "";
        return;
    }
    int num2 = s.find_last_not_of(" ");
    s = s.substr(num1,num2-num1+1);

    int start = 0,end = 0;
    int size = s.length();
    end = size-1;
    //整个字符串倒置
    reverse(s,start,end);
    //两个单词之间有多个空格的情况
    int count = 0;
    for (int i = 0; i < size; i++)
    {
        if(s[i] ==  ' ' && s[i+1] == ' ')continue;
        s[count++]=s[i];            
    }
    if(count<size)s = s.substr(0,count);
    size = s.size();
    start = 0;
    end = -2;
    //其中每个单词倒置
    for (int i = 0; i < size; i++)
    {
        if(s[i] == ' ')
        {
            start = end+2;
            end = i-1;
            reverse(s,start,end);
        }
        if(i == size-1){
            start = end+2;
            end = i;
            reverse(s,start,end);
        }
    }
}

int main(int argc, char **argv)
{
    
    string s = "   a   b ";
    cout<<"before reverse: "<<s<<endl;
    reverseString(s);
    cout<<"after reverse: "<<s<<endl;

    return 0;
}