class Solution {

public:

int lengthOfLastWord(string s) {

int i=0,j=-1,k=-1,lastlen=0;

if(s.size()==0) return 0;

while(i<s.size()){

if(s[i]==' '){

j = i;

}else{

k = i;

lastlen = k-j;

}

i++;

}

return lastlen;

}

};

// j=most recent ' ' index, k= most recent non-' ' index;

//iterate to move j and k. each time update k, we also update our result last-length.

//it is ensured that lastlen is always the length of the last word.