剑指offer-2.24-58.1

class Solution {
    
    
    public String reverseWords(String s) {
    
    
        s = s.trim();
        int i = s.length() - 1;
        int j = i;
        StringBuffer sb = new StringBuffer();
        while (i >= 0) {
    
    
            while (i >= 0 && s.charAt(i) != ' ') {
    
    
                i--;
            }
            sb.append(s.substring(i + 1, j + 1) + " ");
            while (i >= 0 && s.charAt(i) == ' ') {
    
    
                i--;
            }
            j = i;
        } 
        return sb.toString().trim();
    }
}

class Solution {
    
    
    public String reverseWords(String s) {
    
    
        s = s.trim();
        char[] str = s.toCharArray();
        int end = str.length - 1;
        int start = end;
        StringBuffer res = new StringBuffer();
        while (start >= 0) {
    
    
            while (start >= 0 && str[start] != ' ') {
    
    
                start--;
            }
            for (int index = start + 1; index <= end; index++) {
    
    
                res.append(str[index]);
            }
            res.append(' ');
            end = start;
            while (start >= 0 && str[start] == ' ') {
    
    
                start--;
                end--;
            }
        }
        return new String(res).trim();
    }
}