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Input: str = “PAYPALISHIRING”, N = 3 Output: PAHNAPLSIIGYIRInput: str = “ABCDEFGH”, N = 2 Output: ACEGBDFH Explanation: The input string can be written in Zig-Zag fashion in 2 rows as follows: A &nbsp; C &nbsp; &nbsp;E &nbsp; G &nbsp; &nbsp; &nbsp; B &nbsp; D &nbsp; F &nbsp; H Hence, upon reading the above pattern row-wise, the output string is “ACEGBDFH”Print Concatenation of Zig-Zag String in ‘n’ Rows : <a href="https://www.geeksforgeeks.org/concatenation-of-zig-zag-string-in-n-rows/">https://www.geeksforgeeks.org/concatenation-of-zig-zag-string-in-n-rows/</a>

Print Concatenation of Zig-Zag String in ‘n’ Rows

One obvious approach to solve this problem would be to sort the input string and then traverse through the sorted string to find the character which is occurring maximum number of times. Let us see if we can improve on this. So we will use a technique called ‘Hashing’. In this, when we traverse through the string, we would hash each character into an array of ASCII characters.&nbsp; &nbsp;Input string = “test” 1: Construct character count array from the input string. &nbsp;count['e'] = 1 &nbsp;count['s'] = 1 &nbsp;count['t'] = 22: Return the index of maximum value in count array (returns ‘t’).Return maximum occurring character in an input string: <a href="https://www.geeksforgeeks.org/return-maximum-occurring-character-in-the-input-string/">https://www.geeksforgeeks.org/return-maximum-occurring-character-in-the-input-string/</a>

Return maximum occurring character in an input string

A permutation also called an “arrangement number” or “order,” is a rearrangement of the elements of an ordered list S into a one-to-one correspondence with S itself. A string of length n has n! permutation.O(n*n!) Note that there are n! permutations and it requires O(n) time to print a permutation.Write a program to print all permutations of a given string: <a href="https://www.geeksforgeeks.org/write-a-c-program-to-print-all-permutations-of-a-given-string/">https://www.geeksforgeeks.org/write-a-c-program-to-print-all-permutations-of-a-given-string/</a>

Write a program to print all permutations of a given string

Given a text txt[0..n-1] and a pattern pat[0..m-1], write a function search(char pat[], char txt[]) that prints all occurrences of pat[] in txt[]. You may assume that n &gt; m.&nbsp; Examples:Input: &nbsp;txt[] = "THIS IS A TEST TEXT" &nbsp; &nbsp; &nbsp; &nbsp;pat[] = "TEST"Output: Pattern found at index 10Input: &nbsp;txt[] = &nbsp;"AABAACAADAABAABA" &nbsp; &nbsp; &nbsp; &nbsp;pat[] = &nbsp;"AABA"Output: Pattern found at index 0&nbsp; &nbsp; &nbsp; &nbsp;Pattern found at index 9 &nbsp; &nbsp; &nbsp; &nbsp;Pattern found at index 12Naive Algorithm for Pattern Searching:<a href="https://www.geeksforgeeks.org/naive-algorithm-for-pattern-searching/">https://www.geeksforgeeks.org/naive-algorithm-for-pattern-searching/</a>

Naive Algorithm for Pattern Searching

Given two strings where first string may contain wild card characters and second string is a normal string. Write a function that returns true if the two strings match. The following are allowed wild card characters in first string.* --&gt; Matches with 0 or more instances of any character or set of characters. ? --&gt; Matches with any one character. For example, “g*ks” matches with “geeks” match. And string “ge?ks*” matches with “geeksforgeeks” (note ‘*’ at the end of first string). But “g*k” doesn’t match with “gee” as character ‘k’ is not present in second string.String matching where one string contains wildcard characters: <a href="https://www.geeksforgeeks.org/wildcard-character-matching/">https://www.geeksforgeeks.org/wildcard-character-matching/</a>

String matching where one string contains wildcard characters

Given three strings A, B and C. Write a function that checks whether C is an interleaving of A and B. C is said to be interleaving A and B, if it contains all and only characters of A and B and order of all characters in individual strings is preserved.Example:Input: strings: "XXXXZY", "XXY", "XXZ" Output: XXXXZY is interleaved of XXY and XXZ The string XXXXZY can be made by&nbsp; interleaving XXY and XXZ String: &nbsp; &nbsp;XXXXZY String 1: &nbsp; &nbsp;XX Y String 2: &nbsp;XX &nbsp;Z Check whether a given string is an interleaving of two other given strings: <a href="https://www.geeksforgeeks.org/find-if-a-string-is-interleaved-of-two-other-strings-dp-33/">https://www.geeksforgeeks.org/find-if-a-string-is-interleaved-of-two-other-strings-dp-33/</a>

Check whether a given string is an interleaving of two other given strings

Given two strings in lowercase, the task is to make them anagram. The only allowed operation is to remove a character from any string. Find minimum number of characters to be deleted to make both the strings anagram?&nbsp; If two strings contains same data set in any order then strings are called Anagrams.Examples : &nbsp;Input : str1 = "bcadeh" str2 = "hea" Output: 3 We need to remove b, c and d from str1.Remove minimum number of characters so that two strings become anagram: <a href="https://www.geeksforgeeks.org/remove-minimum-number-characters-two-strings-become-anagram/">https://www.geeksforgeeks.org/remove-minimum-number-characters-two-strings-become-anagram/</a>

Remove minimum number of characters so that two strings become anagram

We are given a string. We are also given indexes of first and last characters in string. The task is to reverse the string without using any extra variable.Examples:Input &nbsp;: str = "abc" Output : str = "cba"Input : &nbsp;str = "GeeksforGeeks" Output : str = "skeeGrofskeeG"Reverse string without using any temporary variable: <a href="https://www.geeksforgeeks.org/reverse-string-without-using-any-temporary-variable/">https://www.geeksforgeeks.org/reverse-string-without-using-any-temporary-variable/</a>

Reverse string without using any temporary variable

Given a string s1 and a string s2, write a snippet to say whether s2 is a rotation of s1?&nbsp; (eg given s1 = ABCD and s2 = CDAB, return true, given s1 = ABCD, and s2 = ACBD , return false)Algorithm: areRotations(str1, str2)&nbsp; &nbsp;1. Create a temp string and store concatenation of str1 to &nbsp; &nbsp; &nbsp; str1 in temp. &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;temp = str1.str1 &nbsp; &nbsp;2. If str2 is a substring of temp then str1 and str2 are&nbsp; &nbsp; &nbsp; &nbsp; rotations of each other.&nbsp; &nbsp;Example: &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; str1 = "ABACD" &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; str2 = "CDABA"&nbsp; &nbsp; temp = str1.str1 = "ABACDABACD" &nbsp; &nbsp; Since str2 is a substring of temp, str1 and str2 are&nbsp; &nbsp; &nbsp; rotations of each other.A Program to check if strings are rotations of each other or not: <a href="https://www.geeksforgeeks.org/a-program-to-check-if-strings-are-rotations-of-each-other/">https://www.geeksforgeeks.org/a-program-to-check-if-strings-are-rotations-of-each-other/</a>

A Program to check if strings are rotations of each other or not

Simple solution: First method is to traverse sentence and one by one remove spaces by moving subsequent characters one position back and changing case of first character to capital. It takes O(n*n) time. Efficient solution : We traverse given string, while traversing we copy non space character to result and whenever we encounter space, we ignore it and change next letter to capital. Camel case of a given sentence :<a href=" https://www.geeksforgeeks.org/camel-case-given-sentence/"> https://www.geeksforgeeks.org/camel-case-given-sentence/</a>

Camel case of a given sentence

Given a string S, c1 and c2. Replace character c1 with c2 and c2 with c1. Examples: Input : grrksfoegrrks, c1 = e, c2 = r Output : geeksforgeeks Input : ratul, c1 = t, c2 = h Output : rahul Replace a character c1 with c2 and c2 with c1 in a string S : https://www.geeksforgeeks.org/replace-character-c1-c2-c2-c1-string-s/given a string S, c1 and c2. Replace character c1 with c2 and c2 with c1.&nbsp; Examples:&nbsp; &nbsp;Input : grrksfoegrrks, &nbsp; &nbsp; &nbsp; &nbsp;c1 = e, c2 = r&nbsp; Output : geeksforgeeksInput : ratul, &nbsp; &nbsp; &nbsp; &nbsp;c1 = t, c2 = h&nbsp; Output : rahul Replace a character c1 with c2 and c2 with c1 in a string S &nbsp;: <a href="https://www.geeksforgeeks.org/replace-character-c1-c2-c2-c1-string-s/">https://www.geeksforgeeks.org/replace-character-c1-c2-c2-c1-string-s/</a>

Replace a character c1 with c2 and c2 with c1 in a string S

Given an expression exp of length n consisting of some brackets. The task is to print the bracket numbers when the expression is being parsed. Examples :&nbsp; &nbsp;Input : (a+(b*c))+(d/e) Output : 1 2 2 1 3 3 The highlighted brackets in the given expression (a+(b*c))+(d/e) has been assigned the numbers as: 1 2 2 1 3 3.Input : ((())(())) Output : 1 2 3 3 2 4 5 5 4 1&nbsp;<ol><li>Define a variable left_bnum = 1.</li><li>Create a stack right_bnum.</li><li>Now, for i = 0 to n-1.<ol><li>If exp[i] == ‘(‘, then print left_bnum, push left_bnum on to the stack right_bnum and finally increment left_bnum by 1.</li><li>Else if exp[i] == ‘)’, then print the top element of the stack right_bnum and then pop the top element from the stack.</li></ol></li></ol> Print Bracket Number &nbsp;: <a href="https://www.geeksforgeeks.org/print-bracket-number/">https://www.geeksforgeeks.org/print-bracket-number/</a>

Print Bracket Number

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