557. Reverse Words in a String III[Easy]

今晚复习了Merge k sorted list和construct itinerary，对PriorityQueue有点迷惑。明天复习一下最小堆。

摸一题Easy题睡觉。
几种逆序字符串的方法可以看：http://blog.csdn.net/hhxin635612026/article/details/26944053

    public String reverseWords(String s) {
        int start = 0;
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < s.length(); i++) {
            if (s.charAt(i) == ' ') {
                sb.append(reverse(s.substring(start, i))).append(' ');
                start = i + 1;
            }
        }
        sb.append(reverse(s.substring(start, s.length())));
        return sb.toString();
    }

    private String reverse(String word) {
        StringBuilder sb = new StringBuilder();
        for (int i = word.length() - 1; i >= 0; i--) {
            sb.append(word.charAt(i));
        }
//      几种reverseString的方法：http://blog.csdn.net/hhxin635612026/article/details/26944053
//      StringBuffer sb = new StringBuffer(string);
//      for (int i = 0, j = sb.length() - 1; i < sb.length() >>> 1; i++, j--) {
//          char temp = sb.charAt(i);
//          sb.setCharAt(i, sb.charAt(j));
//          sb.setCharAt(j, temp);
//      }
        return sb.toString();
    }