We are to write the letters of a given stringS, from left to right into lines. Each line has maximum width 100 units, and if writing a letter would cause the width of the line to exceed 100 units, it is written on the next line. We are given an array widths, an array where widths[0] is the width of 'a', widths[1] is the width of 'b', ..., and widths[25] is the width of 'z'.

Now answer two questions: how many lines have at least one character fromS, and what is the width used by the last such line? Return your answer as an integer list of length 2.

这个题依然没啥要说的，每次判断一下是不是需要换行，同时记录最后一行用了多少unit

class Solution {
    public int[] numberOfLines(int[] widths, String S) {
        int[] res = new int[2];

        if(S == null || S.length() == 0)
            return res;

        int lines = 1;
        int units = 0;
        int limit = 100;

        for(int i = 0; i < S.length(); i++) {
            char c = S.charAt(i);

            if(units + widths[c - 'a'] > limit) {
                lines++;
                units = 0;
            }

            units += widths[c - 'a'];
        }

        res[0] = lines;
        res[1] = units;

        return res;
    }
}