388. Longest Absolute File Path

class Solution {
    public int lengthLongestPath(String input) {
        String[] split = input.split("\\\n");
        Stack<Integer> stack = new Stack<>();   // contains string length
        int curLen = 0, maxLen = 0;
        for(String str : split)
        {
            int lvl = getLev(str);
            while(!stack.isEmpty() && stack.size() >= lvl) curLen -= stack.pop();
            if(stack.isEmpty() || stack.size() < lvl)
            {
                int len = getLen(str) + 1;  // + 1 for '/'
                stack.push(len);
                curLen += len;
            }
            if(str.indexOf('.') >= 0) maxLen = Math.max(maxLen, curLen - 1);
        }
        return maxLen;
    }

    int getLen(String str)
    {
        int n = str.length();
        for(int i = 0; i < n; i++) if(str.charAt(i) != '\t') return str.substring(i).length();
        return n;
    }

    int getLev(String str)
    {
        int lv = 1;
        for(char ch : str.toCharArray())
        {
            if(ch != '\t') break;
            lv++;
        }
        return lv;
    }
}