Strings

Given an array of strings, group all the anagrams together. This post explores 2 methods to solve this problem. You can create groups by sorting, or by categorizing using the frequency of characters.

Question: Given a string, Sherlock considers it valid if all the characters in the string occur the same number of time. However, a string is also valid if the frequencies are same after removing any one character. Example 1:Input: str = “aabbcd”Output: NO Example 2:Input: str = “abcc”Output: YES Problem Statement: Let us try to simplify the problem statement first. Sherlock needs to verify if a given string is valid. A string is valid under 2 conditions: All characters of the string appear the same number of times. If you…

Question: Given two strings, determine if they share a common sub-string. Input: “a” and “art” Output: YES Problem Statement Let me try to simplify this problem statement first. You are given two strings, and you need to find out if they share a common sub-string or not. If you can find a common sub-string, output “YES”, else output “NO”. Note that you don’t have to find out what is the common sub-string. Another important aspect of this problem is that the sub-string can be as small as 1 character. A…

Given two strings str1 and str2. Write a function to determine if str1 is an anagram of str2. Example 1:str1 = “listen”, str2 = “silent”Output = True Example 2:str1 = “mississippi”, str2 = “mips”Output = False Terminology: Anagram: Two words or phrases are said to be anagrams of each other if they can be formed by re-shuffling of characters in one of them. Problem Statement: In the given problem we have 2 strings as input. They may be single words or phrases. Return true if they anagrams of each other,…

You are given a string with some repeating characters and some unique characters. Find the first unique character and return its index. Example 1:Input: studyAlgorithmsOutput: 2 Example 2:Input: iLoveToCodeOutput: 0 Problem Statement: I want to simplify the problem statement first before we begin to solve it. An input string consists of some uppercase and lowercase characters which may or may not be repeated. Out of all the unique characters, you need to return the characters that occurs first in the string. In the first example studyAlgorithms, s, and t are…

Terminology: Palindrome: A palindrome is a type of string that reads the same when reading left to right and right to left. An example of a palindrome can be “level”, “racecar”, “kayak” etc. Sub-string: A string formed formed using the characters of the string that may or may not contain repetitions. Brute Force Method: As soon as you see the problem, the most first thought that comes to your mind would be to find all the sub-strings from the given string and keep a track of the longest one that…

Question: Given a set of queries and a pattern, we need to determine if some of those queries can be made from the given pattern by adding one or more lower case character. Output a boolean array where array[i] says true, if the query is possible, else false. Input: queries= {“StudyAlgorithms”, “StudyAlgorithmsTest”, “StanAlluring”, “SimulationAlteration”, “StopStayAlive”}pattern = “StAl” Output: {true, false, true, true, false} Let us try to understand the output.The pattern defined to us is St*Al* (if we see it in terms of a regex) StudyAlgorithms can be made as…

Question: Given a string which consists of lowercase or uppercase letters, find the length of the longest palindromes that can be built with those letters.Input: “abccccdd”Output: 7 In the above example, the longest palindrome in the given string is “dccaccd” whose length is 7. A palindrome consists of letters with equal partners, plus possibly a unique center (without a partner). The letter i from the left has its partner i from the right. For example in ‘abcba’, ‘aa’ and ‘bb’ are partners, and ‘c’ is a unique center. Imagine we…

Question: Given two strings, determine if they share a common sub-string. If they have a common sub-string, print YES else print NO. Input:studyalgorithmsalgosOutput: YES This is one of the easy problems but can get a little tricky, if we do not understand it completely. Let us try to understand the test caseString 1 = “studyalgorithms” String 2 = “algos”The sub-string “algo” is common between both the sub-strings and therefore the answer is “YES“. Let us try to take one more test case. String 1 = “hello” String 2 = “world”The…

Question: Given a string, identify the index of character to be removed to change the string into a palindrome. If the string cannot be converted to palindrome or is already a palindrome just return -1. Input: abckdeedcbaOutput: 3 (0 based indexing) To start off with the problem, we must first understand that there can be two possible ways to make the string a palindrome. If the given string is “bcbc”. If we remove the first ‘b’, the string becomes “cbc” which is a palindrome. If we remove the last ‘c’,…