Refactor

src/s0151_reverse_words_in_a_string.cpp

@@ -1,6 +1,14 @@
 #include "s0151_reverse_words_in_a_string.hpp"
 
-string Solution::reverseWords(string s) {
+void S0151::reverseSubStr(string &s, int begin, int end) {
+  for (; begin < end; ++begin, --end) {
+    char tmp = s[begin];
+    s[begin] = s[end];
+    s[end] = tmp;
+  }
+}
+
+string S0151::reverseWords(string s) {
   if (s.length() == 0) {
     return s;
   }