Leetcode Coding Journey

Key Areas Covered:

• Data Structures: Arrays, Linked Lists, Stacks, Queues, Hash Tables, Trees, Tries, Graphs, Heaps

• Algorithms: Sorting, Searching, Dynamic Programming, Backtracking, Greedy, Divide and Conquer, Bit Manipulation

• Other Topics: String Manipulation, Math, Geometry, Design

Learning Process:

1. Problem Selection: I started with easy problems to build confidence and gradually progressed to medium and hard challenges.

2. Deep Dive: For each problem, I focused on understanding the problem statement, identifying potential solutions, and analyzing time and space complexity.

3. Coding and Testing: I implemented the chosen solution in a programming language (C++ or Python) and thoroughly tested it with various inputs.

4. Learning from Solutions: When stuck, I referred to optimal solutions to understand different approaches and learn new techniques.

5. Practice and Repetition: Consistent practice reinforced concepts and helped me recognize patterns across problems.

Benefits:

• Improved Problem-Solving Skills: Developed a structured approach to breaking down complex problems into smaller subproblems.

• Enhanced Coding Proficiency: Gained fluency in writing clean, efficient, and well-structured code.

• Stronger Foundation: Built a solid understanding of fundamental data structures and algorithms.

• Interview Preparation: LeetCode problems closely align with common interview questions, increasing my confidence for technical assessments.

While the journey was demanding, the results have been invaluable. LeetCode has been an indispensable tool in my development as a computer science student and aspiring software engineer.

Solving 300+ LeetCode Problems: A BTech Computer Science Student's Journey

https://leetcode.com/venkat-0706/

Tackling over 300 LeetCode problems has been an intensive yet rewarding experience. It's significantly enhanced my problem-solving abilities, data structure understanding, and algorithm proficiency.

Leetcode Stats

You can find all of my solutions

https://leetcode.com/submissions/#/1

LeetCode Topics

Two Pointers

0005-longest-palindromic-substring
0015-3sum
0018-4sum
0026-remove-duplicates-from-sorted-array
0027-remove-element
0075-sort-colors
0080-remove-duplicates-from-sorted-array-ii
0125-valid-palindrome
0151-reverse-words-in-a-string
0189-rotate-array
0283-move-zeroes
0345-reverse-vowels-of-a-string
0443-string-compression
1468-check-if-n-and-its-double-exist
1566-check-if-a-word-occurs-as-a-prefix-of-any-word-in-a-sentence
1679-shortest-subarray-to-be-removed-to-make-array-sorted
1894-merge-strings-alternately
2095-minimum-number-of-swaps-to-make-the-string-balanced
2232-adding-spaces-to-a-string
2414-move-pieces-to-obtain-a-string
2488-divide-intervals-into-minimum-number-of-groups
2699-count-the-number-of-fair-pairs
3018-make-string-a-subsequence-using-cyclic-increments
3195-separate-black-and-white-balls

String

0003-longest-substring-without-repeating-characters
0005-longest-palindromic-substring
0043-multiply-strings
0125-valid-palindrome
0140-word-break-ii
0151-reverse-words-in-a-string
0345-reverse-vowels-of-a-string
0443-string-compression
0812-rotate-string
0952-word-subsets
0957-minimum-add-to-make-parentheses-valid
1146-greatest-common-divisor-of-strings
1197-parsing-a-boolean-expression
1302-delete-characters-to-make-fancy-string
1304-longest-happy-string
1350-remove-sub-folders-from-the-filesystem
1502-construct-k-palindrome-strings
1524-string-matching-in-an-array
1537-maximum-score-after-splitting-a-string
1566-check-if-a-word-occurs-as-a-prefix-of-any-word-in-a-sentence
1667-find-kth-bit-in-nth-binary-string
1715-split-a-string-into-the-max-number-of-unique-substrings
1744-number-of-ways-to-form-a-target-string-given-a-dictionary
1894-merge-strings-alternately
1895-minimum-number-of-operations-to-move-all-balls-to-each-box
2059-unique-length-3-palindromic-subsequences
2095-minimum-number-of-swaps-to-make-the-string-balanced
2221-check-if-a-parentheses-string-can-be-valid
2232-adding-spaces-to-a-string
2292-counting-words-with-a-given-prefix
2300-construct-string-with-repeat-limit
2414-move-pieces-to-obtain-a-string
2465-shifting-letters-ii
2580-circular-sentence
2599-take-k-of-each-character-from-left-and-right
2691-count-vowel-strings-in-ranges
3018-make-string-a-subsequence-using-cyclic-increments
3174-minimum-number-of-changes-to-make-binary-string-beautiful
3195-separate-black-and-white-balls
3267-find-longest-special-substring-that-occurs-thrice-i
3309-count-prefix-and-suffix-pairs-i
3451-string-compression-iii
3455-minimum-length-of-string-after-operations

Stack

0780-max-chunks-to-make-sorted
0957-minimum-add-to-make-parentheses-valid
1002-maximum-width-ramp
1197-parsing-a-boolean-expression
1570-final-prices-with-a-special-discount-in-a-shop
1679-shortest-subarray-to-be-removed-to-make-array-sorted
2095-minimum-number-of-swaps-to-make-the-string-balanced
2221-check-if-a-parentheses-string-can-be-valid
3181-find-building-where-alice-and-bob-can-meet

Greedy

0055-jump-game
0122-best-time-to-buy-and-sell-stock-ii
0632-smallest-range-covering-elements-from-k-lists
0670-maximum-swap
0780-max-chunks-to-make-sorted
0957-minimum-add-to-make-parentheses-valid
1304-longest-happy-string
1502-construct-k-palindrome-strings
1766-minimum-number-of-removals-to-make-mountain-array
2089-maximum-matrix-sum
2095-minimum-number-of-swaps-to-make-the-string-balanced
2221-check-if-a-parentheses-string-can-be-valid
2300-construct-string-with-repeat-limit
2488-divide-intervals-into-minimum-number-of-groups
2509-minimize-xor
2616-maximal-score-after-applying-k-operations
2640-maximum-number-of-integers-to-choose-from-a-range-i
2716-prime-subtraction-operation
3195-separate-black-and-white-balls

Array

0001-two-sum
0004-median-of-two-sorted-arrays
0015-3sum
0018-4sum
0026-remove-duplicates-from-sorted-array
0027-remove-element
0040-combination-sum-ii
0048-rotate-image
0055-jump-game
0075-sort-colors
0078-subsets
0080-remove-duplicates-from-sorted-array-ii
0121-best-time-to-buy-and-sell-stock
0122-best-time-to-buy-and-sell-stock-ii
0136-single-number
0140-word-break-ii
0169-majority-element
0189-rotate-array
0238-product-of-array-except-self
0283-move-zeroes
0407-trapping-rain-water-ii
0494-target-sum
0632-smallest-range-covering-elements-from-k-lists
0643-maximum-average-subarray-i
0689-maximum-sum-of-3-non-overlapping-subarrays
0780-max-chunks-to-make-sorted
0787-sliding-puzzle
0854-making-a-large-island
0892-shortest-subarray-with-sum-at-least-k
0952-word-subsets
1002-maximum-width-ramp
1025-minimum-cost-for-tickets
1063-best-sightseeing-pair
1147-flip-columns-for-maximum-number-of-equal-rows
1319-unique-number-of-occurrences
1350-remove-sub-folders-from-the-filesystem
1392-find-the-difference-of-two-arrays
1396-count-servers-that-communicate
1402-count-square-submatrices-with-all-ones
1468-check-if-n-and-its-double-exist
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
1524-string-matching-in-an-array
1528-kids-with-the-greatest-number-of-candies
1570-final-prices-with-a-special-discount-in-a-shop
1679-shortest-subarray-to-be-removed-to-make-array-sorted
1744-number-of-ways-to-form-a-target-string-given-a-dictionary
1755-defuse-the-bomb
1766-minimum-number-of-removals-to-make-mountain-array
1876-map-of-highest-peak
1886-minimum-limit-of-balls-in-a-bag
1895-minimum-number-of-operations-to-move-all-balls-to-each-box
1940-maximum-xor-for-each-query
2054-the-number-of-the-smallest-unoccupied-chair
2089-maximum-matrix-sum
2145-grid-game
2164-two-best-non-overlapping-events
2170-count-number-of-maximum-bitwise-or-subsets
2179-most-beautiful-item-for-each-query
2188-minimized-maximum-of-products-distributed-to-any-store
2232-adding-spaces-to-a-string
2292-counting-words-with-a-given-prefix
2343-count-unguarded-cells-in-the-grid
2356-largest-combination-with-bitwise-and-greater-than-zero
2358-number-of-ways-to-split-array
2375-minimum-obstacle-removal-to-reach-corner
2465-shifting-letters-ii
2488-divide-intervals-into-minimum-number-of-groups
2533-bitwise-xor-of-all-pairings
2545-height-of-binary-tree-after-subtree-removal-queries
2552-maximum-sum-of-distinct-subarrays-with-length-k
2586-longest-square-streak-in-an-array
2616-maximal-score-after-applying-k-operations
2640-maximum-number-of-integers-to-choose-from-a-range-i
2685-first-completely-painted-row-or-column
2691-count-vowel-strings-in-ranges
2692-take-gifts-from-the-richest-pile
2695-find-score-of-an-array-after-marking-all-elements
2699-count-the-number-of-fair-pairs
2711-minimum-time-to-visit-a-cell-in-a-grid
2716-prime-subtraction-operation
2764-maximum-number-of-fish-in-a-grid
2766-find-the-prefix-common-array-of-two-arrays
2792-neighboring-bitwise-xor
2868-continuous-subarrays
2891-maximum-beauty-of-an-array-after-applying-operation
3181-find-building-where-alice-and-bob-can-meet
3219-make-lexicographically-smallest-array-by-swapping-elements
3291-find-if-array-can-be-sorted
3309-count-prefix-and-suffix-pairs-i
3380-shortest-subarray-with-or-at-least-k-ii
3427-special-array-ii
3429-special-array-i
3517-shortest-distance-after-road-addition-queries-i
3522-find-the-power-of-k-size-subarrays-i
3555-final-array-state-after-k-multiplication-operations-i

Hash Table

0001-two-sum
0003-longest-substring-without-repeating-characters
0140-word-break-ii
0169-majority-element
0632-smallest-range-covering-elements-from-k-lists
0952-word-subsets
1147-flip-columns-for-maximum-number-of-equal-rows
1319-unique-number-of-occurrences
1392-find-the-difference-of-two-arrays
1468-check-if-n-and-its-double-exist
1502-construct-k-palindrome-strings
1715-split-a-string-into-the-max-number-of-unique-substrings
2054-the-number-of-the-smallest-unoccupied-chair
2059-unique-length-3-palindromic-subsequences
2300-construct-string-with-repeat-limit
2356-largest-combination-with-bitwise-and-greater-than-zero
2552-maximum-sum-of-distinct-subarrays-with-length-k
2586-longest-square-streak-in-an-array
2599-take-k-of-each-character-from-left-and-right
2640-maximum-number-of-integers-to-choose-from-a-range-i
2677-cousins-in-binary-tree-ii
2685-first-completely-painted-row-or-column
2695-find-score-of-an-array-after-marking-all-elements
2766-find-the-prefix-common-array-of-two-arrays
3267-find-longest-special-substring-that-occurs-thrice-i
3455-minimum-length-of-string-after-operations

Divide and Conquer

0004-median-of-two-sorted-arrays
0169-majority-element

Sorting

0015-3sum
0018-4sum
0075-sort-colors
0169-majority-element
0632-smallest-range-covering-elements-from-k-lists
0780-max-chunks-to-make-sorted
1468-check-if-n-and-its-double-exist
2164-two-best-non-overlapping-events
2179-most-beautiful-item-for-each-query
2488-divide-intervals-into-minimum-number-of-groups
2586-longest-square-streak-in-an-array
2640-maximum-number-of-integers-to-choose-from-a-range-i
2646-kth-largest-sum-in-a-binary-tree
2695-find-score-of-an-array-after-marking-all-elements
2699-count-the-number-of-fair-pairs
2891-maximum-beauty-of-an-array-after-applying-operation
3219-make-lexicographically-smallest-array-by-swapping-elements
3291-find-if-array-can-be-sorted

Counting

0169-majority-element
1396-count-servers-that-communicate
1502-construct-k-palindrome-strings
2300-construct-string-with-repeat-limit
2356-largest-combination-with-bitwise-and-greater-than-zero
3267-find-longest-special-substring-that-occurs-thrice-i
3455-minimum-length-of-string-after-operations

Dynamic Programming

0005-longest-palindromic-substring
0055-jump-game
0121-best-time-to-buy-and-sell-stock
0122-best-time-to-buy-and-sell-stock-ii
0140-word-break-ii
0494-target-sum
0689-maximum-sum-of-3-non-overlapping-subarrays
1025-minimum-cost-for-tickets
1063-best-sightseeing-pair
1402-count-square-submatrices-with-all-ones
1744-number-of-ways-to-form-a-target-string-given-a-dictionary
1766-minimum-number-of-removals-to-make-mountain-array
2164-two-best-non-overlapping-events
2562-count-ways-to-build-good-strings
2586-longest-square-streak-in-an-array

Math

0002-add-two-numbers
0007-reverse-integer
0009-palindrome-number
0029-divide-two-integers
0043-multiply-strings
0048-rotate-image
0050-powx-n
0069-sqrtx
0189-rotate-array
0670-maximum-swap
1146-greatest-common-divisor-of-strings
2716-prime-subtraction-operation
3555-final-array-state-after-k-multiplication-operations-i

Binary Search

0004-median-of-two-sorted-arrays
0069-sqrtx
0374-guess-number-higher-or-lower
0892-shortest-subarray-with-sum-at-least-k
1468-check-if-n-and-its-double-exist
1679-shortest-subarray-to-be-removed-to-make-array-sorted
1766-minimum-number-of-removals-to-make-mountain-array
1886-minimum-limit-of-balls-in-a-bag
2164-two-best-non-overlapping-events
2179-most-beautiful-item-for-each-query
2188-minimized-maximum-of-products-distributed-to-any-store
2586-longest-square-streak-in-an-array
2640-maximum-number-of-integers-to-choose-from-a-range-i
2699-count-the-number-of-fair-pairs
2716-prime-subtraction-operation
2891-maximum-beauty-of-an-array-after-applying-operation
3181-find-building-where-alice-and-bob-can-meet
3267-find-longest-special-substring-that-occurs-thrice-i
3427-special-array-ii

Recursion

0002-add-two-numbers
0021-merge-two-sorted-lists
0050-powx-n
0206-reverse-linked-list
1197-parsing-a-boolean-expression
1667-find-kth-bit-in-nth-binary-string

Monotonic Stack

0780-max-chunks-to-make-sorted
1002-maximum-width-ramp
1570-final-prices-with-a-special-discount-in-a-shop
1679-shortest-subarray-to-be-removed-to-make-array-sorted
3181-find-building-where-alice-and-bob-can-meet

Linked List

0002-add-two-numbers
0021-merge-two-sorted-lists
0206-reverse-linked-list

Sliding Window

0003-longest-substring-without-repeating-characters
0632-smallest-range-covering-elements-from-k-lists
0643-maximum-average-subarray-i
0892-shortest-subarray-with-sum-at-least-k
1755-defuse-the-bomb
2552-maximum-sum-of-distinct-subarrays-with-length-k
2599-take-k-of-each-character-from-left-and-right
2868-continuous-subarrays
2891-maximum-beauty-of-an-array-after-applying-operation
3267-find-longest-special-substring-that-occurs-thrice-i
3380-shortest-subarray-with-or-at-least-k-ii
3522-find-the-power-of-k-size-subarrays-i

Bit Manipulation

0029-divide-two-integers
0078-subsets
0136-single-number
1940-maximum-xor-for-each-query
2059-unique-length-3-palindromic-subsequences
2170-count-number-of-maximum-bitwise-or-subsets
2356-largest-combination-with-bitwise-and-greater-than-zero
2509-minimize-xor
2533-bitwise-xor-of-all-pairings
2766-find-the-prefix-common-array-of-two-arrays
2792-neighboring-bitwise-xor
3291-find-if-array-can-be-sorted
3380-shortest-subarray-with-or-at-least-k-ii
3394-minimum-array-end

Backtracking

0040-combination-sum-ii
0078-subsets
0140-word-break-ii
0494-target-sum
1715-split-a-string-into-the-max-number-of-unique-substrings
2170-count-number-of-maximum-bitwise-or-subsets

Simulation

0043-multiply-strings
1667-find-kth-bit-in-nth-binary-string
2232-adding-spaces-to-a-string
2343-count-unguarded-cells-in-the-grid
2692-take-gifts-from-the-richest-pile
2695-find-score-of-an-array-after-marking-all-elements
3555-final-array-state-after-k-multiplication-operations-i

Matrix

0048-rotate-image
0407-trapping-rain-water-ii
0787-sliding-puzzle
0854-making-a-large-island
1147-flip-columns-for-maximum-number-of-equal-rows
1396-count-servers-that-communicate
1402-count-square-submatrices-with-all-ones
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
1876-map-of-highest-peak
2089-maximum-matrix-sum
2145-grid-game
2343-count-unguarded-cells-in-the-grid
2375-minimum-obstacle-removal-to-reach-corner
2685-first-completely-painted-row-or-column
2711-minimum-time-to-visit-a-cell-in-a-grid
2764-maximum-number-of-fish-in-a-grid

Heap (Priority Queue)

0407-trapping-rain-water-ii
0632-smallest-range-covering-elements-from-k-lists
0892-shortest-subarray-with-sum-at-least-k
1304-longest-happy-string
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
2054-the-number-of-the-smallest-unoccupied-chair
2164-two-best-non-overlapping-events
2300-construct-string-with-repeat-limit
2375-minimum-obstacle-removal-to-reach-corner
2488-divide-intervals-into-minimum-number-of-groups
2616-maximal-score-after-applying-k-operations
2692-take-gifts-from-the-richest-pile
2695-find-score-of-an-array-after-marking-all-elements
2711-minimum-time-to-visit-a-cell-in-a-grid
2868-continuous-subarrays
3181-find-building-where-alice-and-bob-can-meet
3555-final-array-state-after-k-multiplication-operations-i

Trie

0140-word-break-ii
1350-remove-sub-folders-from-the-filesystem
3309-count-prefix-and-suffix-pairs-i

Memoization

0140-word-break-ii

Database

0185-department-top-three-salaries
0584-find-customer-referee
0595-big-countries
1258-article-views-i
1827-invalid-tweets
1908-recyclable-and-low-fat-products

Prefix Sum

0238-product-of-array-except-self
0892-shortest-subarray-with-sum-at-least-k
1537-maximum-score-after-splitting-a-string
1895-minimum-number-of-operations-to-move-all-balls-to-each-box
1940-maximum-xor-for-each-query
2059-unique-length-3-palindromic-subsequences
2145-grid-game
2358-number-of-ways-to-split-array
2465-shifting-letters-ii
2488-divide-intervals-into-minimum-number-of-groups
2691-count-vowel-strings-in-ranges
3427-special-array-ii

Enumeration

2170-count-number-of-maximum-bitwise-or-subsets

Tree

0515-find-largest-value-in-each-tree-row
0988-flip-equivalent-binary-trees
2493-reverse-odd-levels-of-binary-tree
2545-height-of-binary-tree-after-subtree-removal-queries
2558-minimum-number-of-operations-to-sort-a-binary-tree-by-level
2646-kth-largest-sum-in-a-binary-tree
2677-cousins-in-binary-tree-ii
3058-maximum-number-of-k-divisible-components
3439-find-minimum-diameter-after-merging-two-trees

Breadth-First Search

0407-trapping-rain-water-ii
0515-find-largest-value-in-each-tree-row
0684-redundant-connection
0787-sliding-puzzle
0820-find-eventual-safe-states
0854-making-a-large-island
1396-count-servers-that-communicate
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
1558-course-schedule-iv
1876-map-of-highest-peak
2375-minimum-obstacle-removal-to-reach-corner
2493-reverse-odd-levels-of-binary-tree
2545-height-of-binary-tree-after-subtree-removal-queries
2558-minimum-number-of-operations-to-sort-a-binary-tree-by-level
2583-divide-nodes-into-the-maximum-number-of-groups
2646-kth-largest-sum-in-a-binary-tree
2677-cousins-in-binary-tree-ii
2711-minimum-time-to-visit-a-cell-in-a-grid
2764-maximum-number-of-fish-in-a-grid
3439-find-minimum-diameter-after-merging-two-trees
3517-shortest-distance-after-road-addition-queries-i

Binary Tree

0515-find-largest-value-in-each-tree-row
0988-flip-equivalent-binary-trees
2493-reverse-odd-levels-of-binary-tree
2545-height-of-binary-tree-after-subtree-removal-queries
2558-minimum-number-of-operations-to-sort-a-binary-tree-by-level
2646-kth-largest-sum-in-a-binary-tree
2677-cousins-in-binary-tree-ii

Depth-First Search

0515-find-largest-value-in-each-tree-row
0684-redundant-connection
0820-find-eventual-safe-states
0854-making-a-large-island
0988-flip-equivalent-binary-trees
1350-remove-sub-folders-from-the-filesystem
1396-count-servers-that-communicate
1558-course-schedule-iv
2201-valid-arrangement-of-pairs
2246-maximum-employees-to-be-invited-to-a-meeting
2493-reverse-odd-levels-of-binary-tree
2545-height-of-binary-tree-after-subtree-removal-queries
2677-cousins-in-binary-tree-ii
2764-maximum-number-of-fish-in-a-grid
3058-maximum-number-of-k-divisible-components
3439-find-minimum-diameter-after-merging-two-trees

String Matching

0812-rotate-string
1524-string-matching-in-an-array
1566-check-if-a-word-occurs-as-a-prefix-of-any-word-in-a-sentence
2292-counting-words-with-a-given-prefix
3309-count-prefix-and-suffix-pairs-i

Number Theory

2716-prime-subtraction-operation

Queue

0892-shortest-subarray-with-sum-at-least-k
2868-continuous-subarrays

Monotonic Queue

0892-shortest-subarray-with-sum-at-least-k
2868-continuous-subarrays

Graph

0684-redundant-connection
0820-find-eventual-safe-states
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
1558-course-schedule-iv
2201-valid-arrangement-of-pairs
2246-maximum-employees-to-be-invited-to-a-meeting
2375-minimum-obstacle-removal-to-reach-corner
2583-divide-nodes-into-the-maximum-number-of-groups
2711-minimum-time-to-visit-a-cell-in-a-grid
3189-find-champion-ii
3439-find-minimum-diameter-after-merging-two-trees
3517-shortest-distance-after-road-addition-queries-i

Shortest Path

1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
2375-minimum-obstacle-removal-to-reach-corner
2711-minimum-time-to-visit-a-cell-in-a-grid

Eulerian Circuit

2201-valid-arrangement-of-pairs

Ordered Set

2868-continuous-subarrays

Binary Indexed Tree

3181-find-building-where-alice-and-bob-can-meet

Segment Tree

3181-find-building-where-alice-and-bob-can-meet

Interactive

0374-guess-number-higher-or-lower

Rolling Hash

3309-count-prefix-and-suffix-pairs-i

Hash Function

3309-count-prefix-and-suffix-pairs-i

Brainteaser

2533-bitwise-xor-of-all-pairings

Union Find

0684-redundant-connection
0854-making-a-large-island
1396-count-servers-that-communicate
2583-divide-nodes-into-the-maximum-number-of-groups
2764-maximum-number-of-fish-in-a-grid
3219-make-lexicographically-smallest-array-by-swapping-elements

Topological Sort

0820-find-eventual-safe-states
1558-course-schedule-iv
2246-maximum-employees-to-be-invited-to-a-meeting