450 DSA Cracker

Topics (/) / String

Serial
No. Questions

1 Reverse a String (https://leetcode.com/problems/reverse-string/)

2 Check whether a String is Palindrome or not

(https://practice.geeksforgeeks.org/problems/palindrome-string0817/1)

3 Find Duplicate characters in a string (https://www.geeksforgeeks.org/print-all-the-

duplicates-in-the-input-string/)

4 Why strings are immutable in Java? (https://www.baeldung.com/java-string-

immutable)

5 Write a Code to check whether one string is a rotation of another

(https://www.geeksforgeeks.org/a-program-to-check-if-strings-are-rotations-
of-each-other/)

6 Write a Program to check whether a string is a valid shuffle of two strings or not
(https://www.programiz.com/java-programming/examples/check-valid-shuffle-
of-strings)

7 Count and Say problem (https://leetcode.com/problems/count-and-say/)

8 Write a program to find the longest Palindrome in a string.[ Longest palindromic

Substring] (https://practice.geeksforgeeks.org/problems/longest-palindrome-in-
a-string/0)

9 Find Longest Recurring Subsequence in String

(https://practice.geeksforgeeks.org/problems/longest-repeating-subsequence/0)

10 Print all Subsequences of a string. (https://www.geeksforgeeks.org/print-

subsequences-string/)

11 Print all the permutations of the given string

(https://practice.geeksforgeeks.org/problems/permutations-of-a-given-string/0)


Serial
No. Questions

12 Split the Binary string into two substring with equal 0’s and 1’s
(https://www.geeksforgeeks.org/split-the-binary-string-into-substrings-with-
equal-number-of-0s-and-1s/)

13 Word Wrap Problem [VERY IMP].

(https://practice.geeksforgeeks.org/problems/word-wrap/0)

14 EDIT Distance [Very Imp] (https://practice.geeksforgeeks.org/problems/edit-

distance3702/1)

15 Find next greater number with same set of digits. [Very Very IMP]
(https://practice.geeksforgeeks.org/problems/next-permutation/0)

16 Balanced Parenthesis problem.[Imp]

(https://practice.geeksforgeeks.org/problems/parenthesis-checker/0)

17 Word break Problem[ Very Imp]

(https://practice.geeksforgeeks.org/problems/word-break/0)

18 Rabin Karp Algo (https://www.geeksforgeeks.org/rabin-karp-algorithm-for-

pattern-searching/)

19 KMP Algo (https://practice.geeksforgeeks.org/problems/longest-prefix-

suffix2527/1)

20 Convert a Sentence into its equivalent mobile numeric keypad sequence.

(https://www.geeksforgeeks.org/convert-sentence-equivalent-mobile-numeric-
keypad-sequence/)

21 Minimum number of bracket reversals needed to make an expression balanced.

(https://practice.geeksforgeeks.org/problems/count-the-reversals/0)

22 Count All Palindromic Subsequence in a given String.

(https://practice.geeksforgeeks.org/problems/count-palindromic-
subsequences/1)

23 Count of number of given string in 2D character array

(https://www.geeksforgeeks.org/find-count-number-given-string-present-2d-
character-array/)

24 Search a Word in a 2D Grid of characters.

(https://practice.geeksforgeeks.org/problems/find-the-string-in-grid/0)

25 Boyer Moore Algorithm for Pattern Searching.

(https://www.geeksforgeeks.org/boyer-moore-algorithm-for-pattern-searching/)

26 Converting Roman Numerals to Decimal

(https://practice.geeksforgeeks.org/problems/roman-number-to-integer/0)

27 Longest Common Prefix (https://leetcode.com/problems/longest-common-prefix/)
Serial
No. Questions

28 Number of flips to make binary string alternate

(https://practice.geeksforgeeks.org/problems/min-number-of-flips/0)

29 Find the first repeated word in string.

(https://practice.geeksforgeeks.org/problems/second-most-repeated-string-in-
a-sequence/0)

30 Minimum number of swaps for bracket balancing.

(https://practice.geeksforgeeks.org/problems/minimum-swaps-for-bracket-
balancing/0)

31 Find the longest common subsequence between two strings.

(https://practice.geeksforgeeks.org/problems/longest-common-subsequence/0)

32 Program to generate all possible valid IP addresses from given string.

(https://www.geeksforgeeks.org/program-generate-possible-valid-ip-addresses-
given-string/)

33 Write a program to find the smallest window that contains all characters of string
itself. (https://practice.geeksforgeeks.org/problems/smallest-distant-window/0)

34 Rearrange characters in a string such that no two adjacent are same

(https://practice.geeksforgeeks.org/problems/rearrange-characters/0)

35 Minimum characters to be added at front to make string palindrome

(https://www.geeksforgeeks.org/minimum-characters-added-front-make-string-
palindrome/)

36 Given a sequence of words, print all anagrams together

(https://practice.geeksforgeeks.org/problems/k-anagrams-1/0)

37 Find the smallest window in a string containing all characters of another string
(https://practice.geeksforgeeks.org/problems/smallest-window-in-a-string-
containing-all-the-characters-of-another-string/0)

38 Recursively remove all adjacent duplicates

(https://practice.geeksforgeeks.org/problems/consecutive-elements/0)

39 String matching where one string contains wildcard characters

(https://practice.geeksforgeeks.org/problems/wildcard-string-matching/0)

40 Function to find Number of customers who could not get a computer

(https://www.geeksforgeeks.org/function-to-find-number-of-customers-who-
could-not-get-a-computer/)

41 Transform One String to Another using Minimum Number of Given Operation

(https://www.geeksforgeeks.org/transform-one-string-to-another-using-
minimum-number-of-given-operation/)

Serial
No. Questions

42 Check if two given strings are isomorphic to each other

(https://practice.geeksforgeeks.org/problems/isomorphic-strings/0)

43 Recursively print all sentences that can be formed from list of word lists
(https://www.geeksforgeeks.org/recursively-print-all-sentences-that-can-be-
formed-from-list-of-word-lists/)