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()

 1 public class Solution {
 2     public int countSegments(String s) {
 3         if (s==null || s.length()==0) return 0;
 4         String[] strs = s.split(" ");
 5         int count = 0;
 6         for (String str : strs) {
 7             if (str.length() != 0) count++;
 8         }
 9         return count;
10     }
11 }

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

1 public int countSegments(String s) {
2     int res=0;
3     for(int i=0; i<s.length(); i++)
4         if(s.charAt(i)!=‘ ‘ && (i==0 || s.charAt(i-1)==‘ ‘))
5             res++;
6     return res;
7 }