/**
 * 反转字符串
 * @param str string字符串 
 * @return string字符串
 */
char* solve(char* str ) {
    // write code here
    char *p1=str;
char *p2=str;
int temp=0;
while (*p2!='\0')
{
    p2++;
}
p2--;
while (p1<p2)
{
   temp=*p1;
   *p1=*p2;
   *p2=temp;
   p1++;
   p2--;
}
return str;
}