Question

Best Roadmap to prepare Two-Pointers in DSA for coding interviews | 2022 | DesiQnA

Answer 1

Author of this sheet : https://www.linkedin.com/in/kumark1/

Complete DSA Roadmap :- https://www.desiqna.in/4963/roadmap-for-dsa-data-structures-algorithms-kumar-desi-2022 

Desi QnA Two-Pointers Sheet (Make sure to go through set A and set B to have a good preparation level for an interview)

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1)First things first , make sure you go through the Hashing Sheet(complete SET-A and SET-B) before you start this sheet. 

Here is the link : https://www.desiqna.in/4678/best-roadmap-prepare-hashing-coding-interviews-2022-desiqna

2)Go through the concept from here : https://www.geeksforgeeks.org/two-pointers-technique/

 3)Read this : https://leetcode.com/articles/two-pointer-technique/

 4)Watch this video :

 5)Now , it’s the time to start solving some problems. Make sure to solve Set-A and Set-B . Set-C is for the ones who want to reach expert level in the topic.

Set-A : (These problems may involve a mixture of Hashing and Two-Pointers , so make sure you go through the Hashing Sheet of Desi QnA mentioned above).

P1 : https://leetcode.com/problems/remove-duplicates-from-sorted-array/

P2 : https://www.geeksforgeeks.org/given-two-sorted-arrays-number-x-find-pair-whose-sum-closest-x/

P3 : https://www.geeksforgeeks.org/given-sorted-array-number-x-find-pair-array-whose-sum-closest-x/

P4 : https://www.geeksforgeeks.org/find-triplets-array-whose-sum-equal-zero/

P5 : https://www.geeksforgeeks.org/find-a-triplet-that-sum-to-a-given-value/

P6 : https://www.geeksforgeeks.org/find-triplet-sum-two-equals-third-element/

 P7 : https://www.geeksforgeeks.org/find-four-numbers-with-sum-equal-to-given-sum/

 

P8 : https://leetcode.com/problems/squares-of-a-sorted-array/

 

Set - B :

P1 : https://www.geeksforgeeks.org/count-pairs-array-whose-sum-less-x/

(Only focus on method1 of the solution.)

P2 : Find the number of pairs in the array whose sum is greater than equal to k. 'k' is the fixed value provided in the input.

P3 : https://www.geeksforgeeks.org/number-subarrays-sum-exactly-equal-k/

(For Warmup-purpose)

P4 : https://www.geeksforgeeks.org/number-subarrays-sum-less-k/

 (Important to understand the concept)

P5 : https://leetcode.com/problems/subarray-product-less-than-k/

P6 : https://www.geeksforgeeks.org/count-number-of-substrings-having-at-least-k-distinct-characters/

P7 : https://www.geeksforgeeks.org/count-number-of-substrings-with-exactly-k-distinct-characters/

P8 : https://www.geeksforgeeks.org/find-the-longest-substring-with-k-unique-characters-in-a-given-string/

P9 : https://www.lintcode.com/problem/386/

P10 : https://leetcode.com/problems/minimum-size-subarray-sum/

(Very Important) 

P11 : https://leetcode.com/problems/subarrays-with-k-different-integers/

P12 : https://leetcode.com/problems/number-of-substrings-containing-all-three-characters/

P13 : https://leetcode.com/problems/replace-the-substring-for-balanced-string/

P14 : https://leetcode.com/problems/count-number-of-nice-subarrays/

(Enjoy this easy problem if you have come this far ;))

P15 : https://leetcode.com/problems/find-the-longest-equal-subarray/ (please solve this problem)

Set - C : Coming Soon!

Nice readings to go through : 

i)https://leetcode.com/discuss/study-guide/1688903/Solved-all-two-pointers-problems-in-100-days

.

ii)Coming Soon!