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.
Given a text, find all occurrences of a given pattern in it.
Given a list of words, efficiently group all anagrams together. X and Y are anagrams if by rearranging the letters of X, we can get Y using all the original letters of X exactly once.
Given a string, find first K non-repeating characters in it by doing only single traversal of it. For example, if the string is ABCDBAGHCHFAC and K = 3, output would be D G F
Given a list of words and a pattern, find all words in the list that follows same order of characters as that of given pattern.