class Solution {
public:
string reverseWords(string s) {
string res;
int str = 0;
for (int i=0; i<s.length(); i++) {
if (s[i]==' '||i==s.length()-1) {
int j = i==s.length()-1 ? i:i-1;
while (j>=str) {
char tmp = s[str];
s[str] = s[j];
s[j] = tmp;
j--;
str++;
}
str = i+1;
}
}
return s;
}
};
