151. Reverse Words in a String (Inplace) -- unfinished! Write the copy part.

class Solution { public: void reverseHelper(string & s, size_t start, size_t end){ // a helper function to reverse a word, inplace. // start is the start of the word, end is the end of the word in the original string. Inclusive size_t i = start; size_t j = end; while(i < j){ auto tmp = std::move(w[i]); s[i] = s[j]; s[j] = tmp; i++; j--; } } void reverseWords(string &s) { size_t i = 0; while(true){ while(s[i] == ' ' && i < s.size()-1) i++; // shift i to the beginning of the first word size_t j = i; while(s[j] != ' ' && j < s.size()-1) j++; // detect a word! reverseHelper(s, i, j); i = j+1; if (i > s.size()-1) break; } } };