/*
 * 186. Reverse Words in a String II
Total Accepted: 14384
Total Submissions: 49577
Difficulty: Medium
Given an input string, reverse the string word by word. A word is defined as a sequence of non-space characters.

The input string does not contain leading or trailing spaces and the words are always separated by a single space.

For example,
Given s = "the sky is blue",
return "blue is sky the".

Could you do it in-place without allocating extra space?

Related problem: Rotate Array

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Hide Tags String
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 */
public class ReverseWords {

 public static void main(String[] args) {
  ReverseWords rw = new ReverseWords();
  String str = "the sky is blue";
  char[] s = str.toCharArray();
  System.out.println(str);
  rw.reverseWords(s);
  // System.out.println(String.valueOf(s));
 }

 // https://discuss.leetcode.com/topic/8366/my-java-solution-with-explanation
 public void reverseWords(char[] s) {
  // Two step to reverse
  // 1, reverse the whole sentence
  reverse(s, 0, s.length - 1);
  System.out.println(String.valueOf(s));

  // 2, reverse each word
  int start = 0;
  for (int i = 0; i <= s.length; i++) {
   if (i == s.length || s[i] == ' ') {
    System.out.println(i);
    reverse(s, start, i - 1);
    System.out.println(String.valueOf(s));
    start = i + 1;
   }
  }

 }

 public void reverse(char[] s, int start, int end) {
  while (start < end) {
   char temp = s[start];
   s[start] = s[end];
   s[end] = temp;
   start++;
   end--;
  }
 }

}