Given a string sorted in ascending order, find all lexicographically next permutations of it.
Given a string containing all distinct characters, find all permutations of it.
Given a string, find the longest substring of given string containing distinct characters.
Find all substrings of a string that contains all characters of another string. In other words, find all substrings of first string that are anagrams of second string.
Given a string, find all palindromic permutations of it.
Given a string and a positive number k, find the longest substring of given string containing k distinct characters. If k is more than number of distinct characters in the string, return the whole string.
Validate an IP address (IPv4). A valid IPv4 address must be in the form of XXX.XXX.XXX.XXX, where XXX is a number from 0-255.
Run length encoding (RLE) is a very simple form of lossless data compression which runs on sequences having same value occurring many consecutive times and it encode the sequence to store only a single value and its count.
Given a line of text, reverse the text without reversing the individual words.
Given a string and a integer k, print the string in zig-zag form in k rows.
Find the length of longest contiguous substring of a string, such that the length of the substring is 2*N digits and the sum of the leftmost N digits is equal to the sum of the rightmost N digits. If there is no such substring, return 0.
Given a string, inplace remove all occurrences of “AB” and “C” from it.