Find number of customers who could not get any computer
Given an integer representing the capacity of a cyber cafe and a sequence representing entry/exit logs of customers, find the total number of customers who could not get any computer.
Category: String
Find the shortest unique prefix for every word in an array
Given an array of words where no word is the prefix of another, find the shortest unique prefix to identify each word in the array uniquely.
Find all substrings containing exactly `k` distinct characters
Given a string and a positive integer k, find all distinct substrings of any length containing exactly k distinct characters.
Convert a Roman numeral to an Integer
Given a valid roman numeral, convert it to the corresponding integer value.
Convert column name in Excel to the corresponding number
Given a string representing the column name in an Excel sheet, return the number corresponding to the Excel column name.
Find the minimum number of deletions required to convert a string into a palindrome
Given a string, find the minimum number of deletions required to convert it into a palindrome.
Find all lexicographically previous permutations of a string
Given a string sorted in descending order, find all lexicographically previous permutations of it. In the lexicographic order, the words are arranged similarly as they are presumed to appear in a dictionary.
Check a string for repeated substrings
Given a string, check if it has a substring that can be used to construct the string by concatenating multiple copies of it.
Find difference between two strings
Given two strings, where the second string is constructed using all characters of the first string except one, find the character that was skipped in the second string.
Convert an infix expression into a postfix expression
Given an infix expression, convert it to the postfix expression. Assume that the infix expression is a string of tokens without any spaces.
Find correct order of alphabets in a given dictionary of ancient origin
Given a dictionary of ancient origin where the words are arranged alphabetically, find the correct order of alphabets in the ancient language.
Check if a linked list of strings is palindromic
Given a linked list of strings, check whether the concatenation of all values in the list together forms a palindrome. It is not permissible to construct a string out of the linked list nodes and check that string for palindrome.