Leetcode 68 Solution

class Solution {
public:
    vector<string> fullJustify(vector<string>& words, int maxWidth) {
        vector<string> res;

        int l = 0;
        int r = 0;
        int currWidth = 0;

        while (r < words.size())
        {
            if (l == r)
                currWidth += words[r++].size();
            else if (currWidth + words[r].size() + 1 <= maxWidth)
                currWidth += words[r++].size() + 1;
            else
            {
                string localstr = words[l];

                if (r - l > 1)
                {
                    int total_spaces = maxWidth - currWidth + r - l - 1;
                    int local_spaces = total_spaces / (r - l - 1);
                    int left_spaces = total_spaces - local_spaces * (r - l - 1);

                    for (int i = l + 1; i < r; i++)
                    {
                        if (left_spaces > 0)
                        {
                            localstr += string(local_spaces + 1, ' ') + words[i];
                            left_spaces--;
                        }
                        else
                            localstr += string(local_spaces, ' ') + words[i];
                    }
                }
                else
                    localstr += string(maxWidth - localstr.size(), ' ');

                res.push_back(localstr);
                l = r;
                currWidth = 0;
            }
        }

        string last_str = words[l];
        for (int i = l + 1; i < r; i++)
            last_str += " " + words[i];
        last_str += string(maxWidth - last_str.size(), ' ');

        res.push_back(last_str);

        return res;
    }
};