LeetCode_ 58 (length of last word)

Title Description ：
Give you a string s, It consists of several words , Words are separated by some space characters . Return string the last one The length of the word .

word It's just letters 、 The largest substring that does not contain any space characters .

Example 1：
Input ：s = “Hello World”
Output ：5
explain ： The last word is “World”, The length is 5.

Example 2：
Input ：s = " fly me to the moon "
Output ：4
explain ： The last word is “moon”, The length is 4.

Example 3：
Input ：s = “luffy is still joyboy”
Output ：6
explain ： The last word is... In length 6 Of “joyboy”.

Tips ：
1 <= s.length <= 104
s Only English letters and spaces ’ ’ form
s At least one word exists in

class Solution {
    
    public int lengthOfLastWord(String s) {
    
        int res=0;
        for (int i = s.length()-1; i >=0; i--) {
    
            int num=(int)s.charAt(i);
            if((num>122||num<65||(num>90&&num<97))&&res==0)continue;
            else if((num>122||num<65||(num>90&&num<97))&&res!=0)break;
            else if ((num>=97&&num<=122)||(num>=65&&num<=90))   res++;

        }
        return res;
    }
}