public String reverseString(String s) {
StringBuilder sb = new StringBuilder();
for(int i=s.length()-1; i>=0; i--) {
sb.append(s.charAt(i));
}
return sb.toString();
}
public String reverseSentence(String s) {
String r = this.reverseString(s);
int start = 0;
StringBuilder result = new StringBuilder();
for(int i=0; i<=r.length(); i++) {
if( r.length()==i || r.charAt(i)==' ') {
String word = r.substring(start,i);
String reversed = reverseString(word);
result.append(reversed);
if (r.length()!=i){
result.append(' ');
}
start = i +1;
}
}
return result.toString();
}