Java for LeetCode 058 Length of Last Word

Given a string s consists of upper/lower-case alphabets and empty space characters ' ', return the length of last word in the string.

If the last word does not exist, return 0.

Note: A word is defined as a character sequence consists of non-space characters only.

For example,
Given s = "Hello World",
return 5.

解题思路：

从后往前遍历，用一个指针rightIndex表示第一次出现飞空格的位置，然后继续遍历，找出第一次出现空格的位置即可，JAVA实现如下：

   static public int lengthOfLastWord(String s) {
	   	int rightIndex=s.length()-1;
	   	while(rightIndex>=0&&s.charAt(rightIndex)==' ')
	   		rightIndex--;
	   	if(rightIndex<0)
	   		return 0;
        for(int i=rightIndex-1;i>=0;i--)
        	if(s.charAt(i)==' ')
        		return rightIndex-i;
        return rightIndex+1;
    }