186.反转字符串中的单词II

方法：先反转整个字符串再反转单词中的字母

class Solution {
    public void reverseWords(char[] s) {
        reverseCharacters(s,0,s.length-1);
        reverseEachWord(s);

    }
    //反转单词中的字母
    public void reverseEachWord(char[] s){
        int length = s.length;
        int begin = 0;
        for(int i = 0;i<length;i++){
            if(s[i] == ' '){
                reverseCharacters(s,begin,i - 1);
                begin = i+1;
            }
        }
        reverseCharacters(s,begin,length-1);
    }

    //反转整个字符串
    public void reverseCharacters(char[] s, int low ,int high){
        while(low < high){
            char c1 = s[low],c2 = s[high];
            s[low] = c2;
            s[high] = c1;
            low++;
            high--;
        }
    }
}