DSA_Problems

A collection of LeetCode questions to ace the coding interview! - Created using LeetHub v2

LeetCode Topics

Math

0002-add-two-numbers
0007-reverse-integer
0009-palindrome-number
0013-roman-to-integer
0202-happy-number
0412-fizz-buzz
0509-fibonacci-number
0668-kth-smallest-number-in-multiplication-table
1295-find-numbers-with-even-number-of-digits
1569-number-of-ways-to-reorder-array-to-get-same-bst
3723-maximize-sum-of-squares-of-digits

Array

0015-3sum
0016-3sum-closest
0026-remove-duplicates-from-sorted-array
0027-remove-element
0033-search-in-rotated-sorted-array
0034-find-first-and-last-position-of-element-in-sorted-array
0053-maximum-subarray
0056-merge-intervals
0057-insert-interval
0074-search-a-2d-matrix
0075-sort-colors
0088-merge-sorted-array
0152-maximum-product-subarray
0153-find-minimum-in-rotated-sorted-array
0162-find-peak-element
0167-two-sum-ii-input-array-is-sorted
0209-minimum-size-subarray-sum
0215-kth-largest-element-in-an-array
0240-search-a-2d-matrix-ii
0283-move-zeroes
0287-find-the-duplicate-number
0347-top-k-frequent-elements
0378-kth-smallest-element-in-a-sorted-matrix
0410-split-array-largest-sum
0502-ipo
0503-next-greater-element-ii
0525-contiguous-array
0560-subarray-sum-equals-k
0581-shortest-unsorted-continuous-subarray
0621-task-scheduler
0704-binary-search
0713-subarray-product-less-than-k
0724-find-pivot-index
0739-daily-temperatures
0744-find-smallest-letter-greater-than-target
0852-peak-index-in-a-mountain-array
0875-koko-eating-bananas
0904-fruit-into-baskets
0918-maximum-sum-circular-subarray
0974-subarray-sums-divisible-by-k
0977-squares-of-a-sorted-array
0986-interval-list-intersections
1004-max-consecutive-ones-iii
1186-maximum-subarray-sum-with-one-deletion
1295-find-numbers-with-even-number-of-digits
1480-running-sum-of-1d-array
1569-number-of-ways-to-reorder-array-to-get-same-bst
1672-richest-customer-wealth
1749-maximum-absolute-sum-of-any-subarray
1929-concatenation-of-array
2333-minimum-sum-of-squared-difference
2778-sum-of-squares-of-special-elements
2897-apply-operations-on-array-to-maximize-sum-of-squares
2913-subarrays-distinct-element-sum-of-squares-i
2916-subarrays-distinct-element-sum-of-squares-ii
3551-minimum-swaps-to-sort-by-digit-sum
3727-maximum-alternating-sum-of-squares

Matrix

0074-search-a-2d-matrix
0240-search-a-2d-matrix-ii
0378-kth-smallest-element-in-a-sorted-matrix
1672-richest-customer-wealth

Binary Search

0033-search-in-rotated-sorted-array
0034-find-first-and-last-position-of-element-in-sorted-array
0074-search-a-2d-matrix
0153-find-minimum-in-rotated-sorted-array
0162-find-peak-element
0167-two-sum-ii-input-array-is-sorted
0209-minimum-size-subarray-sum
0240-search-a-2d-matrix-ii
0287-find-the-duplicate-number
0378-kth-smallest-element-in-a-sorted-matrix
0410-split-array-largest-sum
0668-kth-smallest-number-in-multiplication-table
0704-binary-search
0713-subarray-product-less-than-k
0744-find-smallest-letter-greater-than-target
0852-peak-index-in-a-mountain-array
0875-koko-eating-bananas
1004-max-consecutive-ones-iii
2333-minimum-sum-of-squared-difference

Dynamic Programming

0022-generate-parentheses
0032-longest-valid-parentheses
0053-maximum-subarray
0152-maximum-product-subarray
0410-split-array-largest-sum
0509-fibonacci-number
0678-valid-parenthesis-string
0918-maximum-sum-circular-subarray
1186-maximum-subarray-sum-with-one-deletion
1569-number-of-ways-to-reorder-array-to-get-same-bst
1749-maximum-absolute-sum-of-any-subarray

Greedy

0409-longest-palindrome
0410-split-array-largest-sum
0502-ipo
0581-shortest-unsorted-continuous-subarray
0621-task-scheduler
0678-valid-parenthesis-string
0767-reorganize-string
0921-minimum-add-to-make-parentheses-valid
1541-minimum-insertions-to-balance-a-parentheses-string
2333-minimum-sum-of-squared-difference
2897-apply-operations-on-array-to-maximize-sum-of-squares
3723-maximize-sum-of-squares-of-digits
3727-maximum-alternating-sum-of-squares

Prefix Sum

0209-minimum-size-subarray-sum
0410-split-array-largest-sum
0525-contiguous-array
0560-subarray-sum-equals-k
0713-subarray-product-less-than-k
0724-find-pivot-index
0974-subarray-sums-divisible-by-k
1004-max-consecutive-ones-iii
1480-running-sum-of-1d-array

Two Pointers

0015-3sum
0016-3sum-closest
0019-remove-nth-node-from-end-of-list
0026-remove-duplicates-from-sorted-array
0027-remove-element
0061-rotate-list
0075-sort-colors
0088-merge-sorted-array
0142-linked-list-cycle-ii
0160-intersection-of-two-linked-lists
0167-two-sum-ii-input-array-is-sorted
0202-happy-number
0234-palindrome-linked-list
0283-move-zeroes
0287-find-the-duplicate-number
0344-reverse-string
0581-shortest-unsorted-continuous-subarray
0844-backspace-string-compare
0876-middle-of-the-linked-list
0977-squares-of-a-sorted-array
0986-interval-list-intersections

Sorting

0015-3sum
0016-3sum-closest
0056-merge-intervals
0075-sort-colors
0088-merge-sorted-array
0215-kth-largest-element-in-an-array
0347-top-k-frequent-elements
0378-kth-smallest-element-in-a-sorted-matrix
0502-ipo
0581-shortest-unsorted-continuous-subarray
0621-task-scheduler
0767-reorganize-string
0977-squares-of-a-sorted-array
2333-minimum-sum-of-squared-difference
3551-minimum-swaps-to-sort-by-digit-sum
3727-maximum-alternating-sum-of-squares

Quicksort

0056-merge-intervals
0075-sort-colors

Bubble Sort

0075-sort-colors

Sliding Window

0003-longest-substring-without-repeating-characters
0076-minimum-window-substring
0209-minimum-size-subarray-sum
0424-longest-repeating-character-replacement
0713-subarray-product-less-than-k
0904-fruit-into-baskets
1004-max-consecutive-ones-iii

Simulation

0412-fizz-buzz
0844-backspace-string-compare
1929-concatenation-of-array
3498-reverse-degree-of-a-string

String

0003-longest-substring-without-repeating-characters
0013-roman-to-integer
0017-letter-combinations-of-a-phone-number
0020-valid-parentheses
0022-generate-parentheses
0032-longest-valid-parentheses
0076-minimum-window-substring
0301-remove-invalid-parentheses
0344-reverse-string
0383-ransom-note
0387-first-unique-character-in-a-string
0409-longest-palindrome
0412-fizz-buzz
0424-longest-repeating-character-replacement
0678-valid-parenthesis-string
0767-reorganize-string
0844-backspace-string-compare
0856-score-of-parentheses
0921-minimum-add-to-make-parentheses-valid
1021-remove-outermost-parentheses
1047-remove-all-adjacent-duplicates-in-string
1189-maximum-number-of-balloons
1209-remove-all-adjacent-duplicates-in-string-ii
1541-minimum-insertions-to-balance-a-parentheses-string
1614-maximum-nesting-depth-of-the-parentheses
3498-reverse-degree-of-a-string

Hash Table

0003-longest-substring-without-repeating-characters
0013-roman-to-integer
0017-letter-combinations-of-a-phone-number
0076-minimum-window-substring
0142-linked-list-cycle-ii
0160-intersection-of-two-linked-lists
0202-happy-number
0347-top-k-frequent-elements
0383-ransom-note
0387-first-unique-character-in-a-string
0409-longest-palindrome
0424-longest-repeating-character-replacement
0525-contiguous-array
0560-subarray-sum-equals-k
0621-task-scheduler
0767-reorganize-string
0904-fruit-into-baskets
0974-subarray-sums-divisible-by-k
1189-maximum-number-of-balloons
2897-apply-operations-on-array-to-maximize-sum-of-squares
2913-subarrays-distinct-element-sum-of-squares-i
2916-subarrays-distinct-element-sum-of-squares-ii
3551-minimum-swaps-to-sort-by-digit-sum

Linked List

0002-add-two-numbers
0019-remove-nth-node-from-end-of-list
0023-merge-k-sorted-lists
0024-swap-nodes-in-pairs
0025-reverse-nodes-in-k-group
0061-rotate-list
0083-remove-duplicates-from-sorted-list
0092-reverse-linked-list-ii
0142-linked-list-cycle-ii
0160-intersection-of-two-linked-lists
0203-remove-linked-list-elements
0206-reverse-linked-list
0234-palindrome-linked-list
0328-odd-even-linked-list
0876-middle-of-the-linked-list

Stack

0020-valid-parentheses
0032-longest-valid-parentheses
0234-palindrome-linked-list
0503-next-greater-element-ii
0581-shortest-unsorted-continuous-subarray
0678-valid-parenthesis-string
0739-daily-temperatures
0844-backspace-string-compare
0856-score-of-parentheses
0921-minimum-add-to-make-parentheses-valid
1021-remove-outermost-parentheses
1047-remove-all-adjacent-duplicates-in-string
1209-remove-all-adjacent-duplicates-in-string-ii
1541-minimum-insertions-to-balance-a-parentheses-string
1614-maximum-nesting-depth-of-the-parentheses

Monotonic Stack

0503-next-greater-element-ii
0581-shortest-unsorted-continuous-subarray
0739-daily-temperatures

Floyd's Cycle Finding Algorithm

0142-linked-list-cycle-ii
0202-happy-number
0287-find-the-duplicate-number

Bit Manipulation

0287-find-the-duplicate-number
2897-apply-operations-on-array-to-maximize-sum-of-squares

Pigeonhole Principle

0287-find-the-duplicate-number

Recursion

0002-add-two-numbers
0024-swap-nodes-in-pairs
0025-reverse-nodes-in-k-group
0203-remove-linked-list-elements
0206-reverse-linked-list
0234-palindrome-linked-list
0509-fibonacci-number

Divide and Conquer

0023-merge-k-sorted-lists
0053-maximum-subarray
0215-kth-largest-element-in-an-array
0240-search-a-2d-matrix-ii
0347-top-k-frequent-elements
0918-maximum-sum-circular-subarray
1569-number-of-ways-to-reorder-array-to-get-same-bst

Queue

0387-first-unique-character-in-a-string
0918-maximum-sum-circular-subarray

Monotonic Queue

0918-maximum-sum-circular-subarray

Bracket Sequences

0020-valid-parentheses
0022-generate-parentheses
0032-longest-valid-parentheses
0678-valid-parenthesis-string
0856-score-of-parentheses
0921-minimum-add-to-make-parentheses-valid
1021-remove-outermost-parentheses
1541-minimum-insertions-to-balance-a-parentheses-string
1614-maximum-nesting-depth-of-the-parentheses

Sweep Line

0986-interval-list-intersections

Database

0176-second-highest-salary
0180-consecutive-numbers
0185-department-top-three-salaries
0196-delete-duplicate-emails
0197-rising-temperature
0550-game-play-analysis-iv
0570-managers-with-at-least-5-direct-reports
0577-employee-bonus
0584-find-customer-referee
0585-investments-in-2016
0595-big-countries
0596-classes-with-at-least-5-students
0602-friend-requests-ii-who-has-the-most-friends
0610-triangle-judgement
0619-biggest-single-number
0620-not-boring-movies
0626-exchange-seats
1045-customers-who-bought-all-products
1068-product-sales-analysis-i
1070-product-sales-analysis-iii
1075-project-employees-i
1141-user-activity-for-the-past-30-days-i
1148-article-views-i
1164-product-price-at-a-given-date
1174-immediate-food-delivery-ii
1193-monthly-transactions-i
1204-last-person-to-fit-in-the-bus
1211-queries-quality-and-percentage
1251-average-selling-price
1280-students-and-examinations
1321-restaurant-growth
1327-list-the-products-ordered-in-a-period
1341-movie-rating
1378-replace-employee-id-with-the-unique-identifier
1484-group-sold-products-by-the-date
1517-find-users-with-valid-e-mails
1527-patients-with-a-condition
1581-customer-who-visited-but-did-not-make-any-transactions
1633-percentage-of-users-attended-a-contest
1661-average-time-of-process-per-machine
1667-fix-names-in-a-table
1683-invalid-tweets
1729-find-followers-count
1731-the-number-of-employees-which-report-to-each-employee
1757-recyclable-and-low-fat-products
1789-primary-department-for-each-employee
1907-count-salary-categories
1934-confirmation-rate
1978-employees-whose-manager-left-the-company
2356-number-of-unique-subjects-taught-by-each-teacher

Backtracking

0017-letter-combinations-of-a-phone-number
0022-generate-parentheses
0301-remove-invalid-parentheses

Counting

0347-top-k-frequent-elements
0383-ransom-note
0387-first-unique-character-in-a-string
0621-task-scheduler
0767-reorganize-string
1189-maximum-number-of-balloons

Breadth-First Search

0301-remove-invalid-parentheses

Ternary Search

0852-peak-index-in-a-mountain-array

Heap (Priority Queue)

0023-merge-k-sorted-lists
0215-kth-largest-element-in-an-array
0347-top-k-frequent-elements
0378-kth-smallest-element-in-a-sorted-matrix
0502-ipo
0621-task-scheduler
0767-reorganize-string
2333-minimum-sum-of-squared-difference

Enumeration

2778-sum-of-squares-of-special-elements

Quickselect

0215-kth-largest-element-in-an-array
0347-top-k-frequent-elements

Bucket Sort

0347-top-k-frequent-elements

Binary Indexed Tree

2913-subarrays-distinct-element-sum-of-squares-i
2916-subarrays-distinct-element-sum-of-squares-ii

Segment Tree

2913-subarrays-distinct-element-sum-of-squares-i
2916-subarrays-distinct-element-sum-of-squares-ii

Merge Sort

0023-merge-k-sorted-lists

Tournament Sort

0023-merge-k-sorted-lists

Memoization

0509-fibonacci-number
1569-number-of-ways-to-reorder-array-to-get-same-bst

Tree

1569-number-of-ways-to-reorder-array-to-get-same-bst

Union-Find

1569-number-of-ways-to-reorder-array-to-get-same-bst

Binary Search Tree

1569-number-of-ways-to-reorder-array-to-get-same-bst

Combinatorics

1569-number-of-ways-to-reorder-array-to-get-same-bst

Binary Tree

1569-number-of-ways-to-reorder-array-to-get-same-bst

Fermat's Little Theorem

1569-number-of-ways-to-reorder-array-to-get-same-bst