LeetCode58. 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.

#include<string>
#include<iostream>
using namespace std;
class Solution {
public:
int lengthOfLastWord(string s) {
int n=s.length(),res=0;
if(n==0) return res;
int idx=n-1;
while((s[idx]==' ')&&(idx!=0)){
idx--;
}
while((idx!=-1)&&(s[idx]!=' ')){
res++;
idx--;
}
return res;
}
};
void main(){
string s="a  ";
Solution So;
int res=So.lengthOfLastWord(s);
cout<<res<<endl;

}