77. Length of Last Word

58. Length of Last Word

Total Accepted: 94158 Total Submissions: 319690 Difficulty: Easy

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.

题意：返回字符串中最后一个词的长度，主要考虑边界问题

class Solution {
public:
int lengthOfLastWord(string s) {
int n=s.size();
if(n==0)return 0;//为空返回0
int fir,sec=n-1;
while(sec>=0&&s[sec]==' ')--sec;//从面找到倒数第一个不为空的字符
if(sec<0)return 0;    //如果-1，说明没有不为空的
else fir = sec-1;
while(fir>=0&&s[fir]!=' ')--fir;//找到该单词第一个字符
return sec-fir;                 //返回长度
}
};