388. Longest Absolute File Path

The string "dir\n\tsubdir1\n\t\tfile1.ext\n\t\tsubsubdir1\n\tsubdir2\n\t\tsubsubdir2\n\t\t\tfile2.ext" represents:

dir
    subdir1
        file1.ext
        subsubdir1
    subdir2
        subsubdir2
            file2.ext
            
"dir/subdir2/subsubdir2/file2.ext", and its length is 32 

public class Solution {
    public int lengthLongestPath(String input) {
        String[] paths = input.split("\n");
        int[] stk = new int[paths.length + 1];
        int maxLen = 0;
        // 路径是定好的，覆盖的时候已经走完上一层，放心覆盖。
        for(String str: paths){
            int lev = str.lastIndexOf("\t") + 1;        
                               // 路径长度         “/” 占一格
            stk[lev+1] = stk[lev] + str.length() - lev + 1;
            if(str.contains("."))  maxLen = Math.max(maxLen, stk[lev+1]-1);   // 结尾处没有“/”, 所以减一
        }
        return maxLen;
    }
}

public class Solution {
    public int lengthLongestPath(String input) {
        Deque<Integer> stk = new ArrayDeque<Integer>();
        stk.push(0);
        int res = 0;
        
        for(String str: input.split("\n")){
            int lev = str.lastIndexOf("\t") +1;
            while(lev+1 < stk.size()) stk.pop();
            int len = stk.peek() + str.length() - lev + 1;
            stk.push(len);
            if(str.contains(".")) res = Math.max(res, len - 1);
        }
        return res;
    }
}