In a file system where both directories and files are stored, we are given a string representation of the system. The string includes the directory structure, with tab characters (’\t’) representing subdirectories and newline characters (’\n’) representing file and directory boundaries. Each directory and file has a unique absolute path. Compute the length of the longest absolute path to a file. If no file exists, return 0.
You are given a string that is encoded using the pattern k[encoded_string], where the substring inside the square brackets is repeated exactly k times. Your task is to decode the string by expanding it according to the given encoding rule.
Given a string num representing a non-negative integer and an integer k, remove k digits from num such that the remaining number is the smallest possible integer.
You are given two non-empty linked lists where each node contains a single digit representing a non-negative integer. Add the two numbers and return the sum as a linked list, ensuring the most significant digit is at the head of the list.
Given an array of integers, determine if there exists a subsequence of three integers nums[i], nums[j], nums[k] where i < j < k and nums[i] < nums[k] < nums[j]. Return true if such a subsequence exists, otherwise return false.
