Text Justification [LeetCode]

Problem Description:http://oj.leetcode.com/problems/text-justification/

Note: Just be careful about boundary when implementing it.

 class Solution {
 public:
     string genNormalLine(vector<string> &words, int L, int start, int end){
         int word_count = end - start + ;
         string line;
         if(word_count == ){
             line.append(words[start]);
             line.append(L-line.size(), ' ');
         }else{
             int slot_num = word_count - ;
             int words_size = ;
             for(int i = start; i <= end; i++)
                 words_size += words[i].size();

             int space_num = L - words_size;
             int reminder = space_num % slot_num;
             int quotient = space_num / slot_num;
             line.append(words[start]);
             for(int i = start + ; i <= end; i++) {
                 if(reminder >  ){
                     line.append(quotient + , ' ');
                     reminder --;
                 } else {
                     line.append(quotient, ' ');
                 }

                 line.append(words[i]);
             }
         }

         return line;
     }

     vector<string> fullJustify(vector<string> &words, int L) {
         // Note: The Solution object is instantiated only once and is reused by each test case.
         vector<string> formatted_lines;
         if(words.size() == )
             return formatted_lines;
         for(int i = ; i < words.size();){
             int length = ;

             int j = i;
             for(; j < words.size(); j ++){
                 if( j == i)
                     length += words[j].size();
                 else
                     length += (+ words[j].size());

                 if(length > L)
                     break;
             }

             //put words in a line
             if(j == words.size()) {
                 //last line
                 string line;
                 line.append(words[i]);
                 for(int k = i + ; k < words.size(); k++){
                     line.push_back(' ');
                     line.append(words[k]);
                 }
                 if(line.size() < L){
                     line.append(L-line.size(), ' ');
                 }

                 formatted_lines.push_back(line);
             }else {
                 //normal line
                 formatted_lines.push_back(genNormalLine(words,L, i, j - ));
             }

             //next start index
             i = j;
         }

         return formatted_lines;
     }
 };