Leetcode: Number of Segments in a String

Count the number of segments in a string, where a segment is defined to be a contiguous sequence of non-space characters.

Please note that the string does not contain any non-printable characters.

Example:

Input: "Hello, my name is John"
Output: 5

用split()

 public class Solution {
     public int countSegments(String s) {
         if (s==null || s.length()==0) return 0;
         String[] strs = s.split(" ");
         int count = 0;
         for (String str : strs) {
             if (str.length() != 0) count++;
         }
         return count;
     }
 }

不用API, better solution, O(N) time O(1) space

 public int countSegments(String s) {
     int res=0;
     for(int i=0; i<s.length(); i++)
         if(s.charAt(i)!=' ' && (i==0 || s.charAt(i-1)==' '))
             res++;
     return res;
 }