Evaluate a given expression
Given an expression containing numeric operands with addition and subtraction operators, evaluate it. The expression may contain sub-expressions enclosed in opening and closing braces.
Category: String
Construct smallest number after removing k digits from a string
Given the string representation of a non-negative integer and an integer k, find the smallest number that remains after taking out k digits from it.
Construct a string from an encoded sequence
A string that may contain multiple consecutive instances of the same value is encoded to only store that value and its count. Given such an encoded sequence, decode it.
Find length of the longest palindrome possible from a string
Given a string, find the length of the longest palindrome possible from its characters.
Check if a string can be constructed from another string
Given two strings, check if the second string can be constructed from characters of the first string, where each character of the first string can be used only once in the second string.
Determine if a string is a subsequence of another string
Given two strings, check if the second string is a subsequence of the first string.
Print all pairs of anagrams in a set of strings
Given a set of strings, print all pairs of anagrams together. Two strings, X and Y, are called anagrams if we can get a string Y by rearranging the letters of the string X and using all the characters of the string X exactly once.
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.
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.