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

LeetCode Topics

Math

0012-integer-to-roman
0013-roman-to-integer
0066-plus-one
0067-add-binary
0070-climbing-stairs
0168-excel-sheet-column-title
0172-factorial-trailing-zeroes
0202-happy-number
0231-power-of-two
0263-ugly-number
0268-missing-number
0326-power-of-three
0342-power-of-four
0405-convert-a-number-to-hexadecimal
0412-fizz-buzz
0504-base-7
0507-perfect-number
0866-rectangle-overlap
0900-reordered-power-of-2
0950-x-of-a-kind-in-a-deck-of-cards
1010-powerful-integers
1013-fibonacci-number
1115-valid-boomerang
1411-convert-binary-number-in-a-linked-list-to-integer
1448-maximum-69-number
1529-max-difference-you-can-get-from-changing-an-integer
1635-number-of-good-pairs
1993-sum-of-all-subset-xor-totals
2037-count-square-sum-triples
2432-number-of-zero-filled-subarrays
2491-smallest-even-multiple
2650-split-with-minimum-sum
2722-prime-in-diagonal
3581-the-two-sneaky-numbers-of-digitville
3600-find-the-k-th-character-in-string-game-i

Number Theory

0950-x-of-a-kind-in-a-deck-of-cards
2491-smallest-even-multiple
2722-prime-in-diagonal

Hash Table

0001-two-sum
0003-longest-substring-without-repeating-characters
0012-integer-to-roman
0013-roman-to-integer
0017-letter-combinations-of-a-phone-number
0128-longest-consecutive-sequence
0141-linked-list-cycle
0160-intersection-of-two-linked-lists
0169-majority-element
0202-happy-number
0205-isomorphic-strings
0217-contains-duplicate
0229-majority-element-ii
0268-missing-number
0290-word-pattern
0350-intersection-of-two-arrays-ii
0383-ransom-note
0389-find-the-difference
0395-longest-substring-with-at-least-k-repeating-characters
0424-longest-repeating-character-replacement
0438-find-all-anagrams-in-a-string
0442-find-all-duplicates-in-an-array
0448-find-all-numbers-disappeared-in-an-array
0496-next-greater-element-i
0594-longest-harmonious-subsequence
0645-set-mismatch
0900-reordered-power-of-2
0920-uncommon-words-from-two-sentences
0940-fruit-into-baskets
0950-x-of-a-kind-in-a-deck-of-cards
0991-array-of-doubled-pairs
1010-powerful-integers
1039-find-the-town-judge
1217-relative-sort-array
1256-rank-transform-of-an-array
1319-unique-number-of-occurrences
1510-find-lucky-integer-in-an-array
1557-check-if-a-string-contains-all-binary-codes-of-size-k
1635-number-of-good-pairs
1741-sort-array-by-increasing-frequency
1904-second-largest-digit-in-a-string
2122-count-special-quadruplets
2204-find-subsequence-of-length-k-with-the-largest-sum
2502-sort-the-people
2524-largest-positive-integer-that-exists-with-its-negative
2561-number-of-distinct-averages
2634-minimum-common-value
2695-find-score-of-an-array-after-marking-all-elements
3044-minimum-operations-to-collect-elements
3242-count-elements-with-maximum-frequency
3428-find-the-xor-of-numbers-which-appear-twice
3581-the-two-sneaky-numbers-of-digitville
3753-maximum-difference-between-even-and-odd-frequency-i
3788-maximum-unique-subarray-sum-after-deletion

Linked List

0083-remove-duplicates-from-sorted-list
0141-linked-list-cycle
0160-intersection-of-two-linked-lists
0203-remove-linked-list-elements
0206-reverse-linked-list
1411-convert-binary-number-in-a-linked-list-to-integer

Two Pointers

0005-longest-palindromic-substring
0015-3sum
0018-4sum
0026-remove-duplicates-from-sorted-array
0027-remove-element
0028-find-the-index-of-the-first-occurrence-in-a-string
0080-remove-duplicates-from-sorted-array-ii
0088-merge-sorted-array
0125-valid-palindrome
0141-linked-list-cycle
0151-reverse-words-in-a-string
0160-intersection-of-two-linked-lists
0167-two-sum-ii-input-array-is-sorted
0202-happy-number
0283-move-zeroes
0344-reverse-string
0345-reverse-vowels-of-a-string
0350-intersection-of-two-arrays-ii
0392-is-subsequence
0443-string-compression
0455-assign-cookies
0541-reverse-string-ii
0658-find-k-closest-elements
0941-sort-array-by-parity
0958-sort-array-by-parity-ii
0979-di-string-match
1019-squares-of-a-sorted-array
1168-duplicate-zeros
2320-find-all-k-distant-indices-in-an-array
2497-maximum-matching-of-players-with-trainers
2524-largest-positive-integer-that-exists-with-its-negative
2561-number-of-distinct-averages
2634-minimum-common-value

Database

0175-combine-two-tables
0176-second-highest-salary
0180-consecutive-numbers
0181-employees-earning-more-than-their-managers
0182-duplicate-emails
0183-customers-who-never-order
0184-department-highest-salary
0196-delete-duplicate-emails
0197-rising-temperature
0577-employee-bonus
0586-customer-placing-the-largest-number-of-orders
0596-classes-with-at-least-5-students
0610-triangle-judgement
0619-biggest-single-number
0620-not-boring-movies
0627-swap-salary
1136-actors-and-directors-who-cooperated-at-least-three-times
1153-product-sales-analysis-i
1161-project-employees-i
1174-sales-analysis-iii
1179-game-play-analysis-i
1245-user-activity-for-the-past-30-days-i
1301-reformat-department-table
1338-queries-quality-and-percentage
1390-average-selling-price
1415-students-and-examinations
1462-list-the-products-ordered-in-a-period
1509-replace-employee-id-with-the-unique-identifier
1541-top-travellers
1625-group-sold-products-by-the-date
1670-patients-with-a-condition

Array

0001-two-sum
0015-3sum
0018-4sum
0026-remove-duplicates-from-sorted-array
0027-remove-element
0053-maximum-subarray
0066-plus-one
0080-remove-duplicates-from-sorted-array-ii
0088-merge-sorted-array
0118-pascals-triangle
0121-best-time-to-buy-and-sell-stock
0128-longest-consecutive-sequence
0136-single-number
0164-maximum-gap
0167-two-sum-ii-input-array-is-sorted
0169-majority-element
0198-house-robber
0209-minimum-size-subarray-sum
0217-contains-duplicate
0228-summary-ranges
0229-majority-element-ii
0260-single-number-iii
0268-missing-number
0283-move-zeroes
0350-intersection-of-two-arrays-ii
0414-third-maximum-number
0442-find-all-duplicates-in-an-array
0448-find-all-numbers-disappeared-in-an-array
0455-assign-cookies
0496-next-greater-element-i
0498-diagonal-traverse
0503-next-greater-element-ii
0540-single-element-in-a-sorted-array
0594-longest-harmonious-subsequence
0643-maximum-average-subarray-i
0645-set-mismatch
0658-find-k-closest-elements
0682-baseball-game
0739-daily-temperatures
0745-find-smallest-letter-greater-than-target
0747-min-cost-climbing-stairs
0792-binary-search
0940-fruit-into-baskets
0941-sort-array-by-parity
0950-x-of-a-kind-in-a-deck-of-cards
0958-sort-array-by-parity-ii
0979-di-string-match
0981-delete-columns-to-make-sorted
0991-array-of-doubled-pairs
1019-squares-of-a-sorted-array
1039-find-the-town-judge
1115-valid-boomerang
1168-duplicate-zeros
1217-relative-sort-array
1221-element-appearing-more-than-25-in-sorted-array
1256-rank-transform-of-an-array
1293-three-consecutive-odds
1319-unique-number-of-occurrences
1402-count-square-submatrices-with-all-ones
1496-lucky-numbers-in-a-matrix
1510-find-lucky-integer-in-an-array
1570-final-prices-with-a-special-discount-in-a-shop
1584-average-salary-excluding-the-minimum-and-maximum-salary
1586-longest-subarray-of-1s-after-deleting-one-element
1628-count-submatrices-with-all-ones
1635-number-of-good-pairs
1704-special-positions-in-a-binary-matrix
1741-sort-array-by-increasing-frequency
1993-sum-of-all-subset-xor-totals
2020-remove-one-element-to-make-the-array-strictly-increasing
2042-maximum-product-difference-between-two-pairs
2122-count-special-quadruplets
2132-convert-1d-array-into-2d-array
2144-maximum-difference-between-increasing-elements
2170-count-number-of-maximum-bitwise-or-subsets
2199-two-furthest-houses-with-different-colors
2204-find-subsequence-of-length-k-with-the-largest-sum
2267-minimum-difference-in-sums-after-removal-of-elements
2316-count-hills-and-valleys-in-an-array
2320-find-all-k-distant-indices-in-an-array
2387-partition-array-such-that-maximum-difference-is-k
2432-number-of-zero-filled-subarrays
2469-longest-subsequence-with-limited-sum
2497-maximum-matching-of-players-with-trainers
2502-sort-the-people
2503-longest-subarray-with-maximum-bitwise-and
2524-largest-positive-integer-that-exists-with-its-negative
2536-determine-if-two-events-have-conflict
2561-number-of-distinct-averages
2614-maximum-count-of-positive-integer-and-negative-integer
2634-minimum-common-value
2675-find-the-width-of-columns-of-a-grid
2695-find-score-of-an-array-after-marking-all-elements
2722-prime-in-diagonal
2756-buy-two-chocolates
2836-neither-minimum-nor-maximum
2844-sum-of-squares-of-special-elements
3044-minimum-operations-to-collect-elements
3164-last-visited-integers
3241-divide-array-into-arrays-with-max-difference
3242-count-elements-with-maximum-frequency
3251-maximum-area-of-longest-diagonal-rectangle
3263-divide-an-array-into-subarrays-with-minimum-cost-i
3311-ant-on-the-boundary
3398-make-a-square-with-the-same-color
3428-find-the-xor-of-numbers-which-appear-twice
3490-find-the-maximum-length-of-valid-subsequence-i
3581-the-two-sneaky-numbers-of-digitville
3723-sum-of-good-numbers
3788-maximum-unique-subarray-sum-after-deletion
3790-fruits-into-baskets-ii

String

0003-longest-substring-without-repeating-characters
0005-longest-palindromic-substring
0006-zigzag-conversion
0012-integer-to-roman
0013-roman-to-integer
0014-longest-common-prefix
0017-letter-combinations-of-a-phone-number
0020-valid-parentheses
0028-find-the-index-of-the-first-occurrence-in-a-string
0058-length-of-last-word
0067-add-binary
0125-valid-palindrome
0151-reverse-words-in-a-string
0168-excel-sheet-column-title
0205-isomorphic-strings
0290-word-pattern
0316-remove-duplicate-letters
0344-reverse-string
0345-reverse-vowels-of-a-string
0383-ransom-note
0389-find-the-difference
0392-is-subsequence
0395-longest-substring-with-at-least-k-repeating-characters
0405-convert-a-number-to-hexadecimal
0412-fizz-buzz
0424-longest-repeating-character-replacement
0438-find-all-anagrams-in-a-string
0443-string-compression
0541-reverse-string-ii
0551-student-attendance-record-i
0920-uncommon-words-from-two-sentences
0979-di-string-match
0981-delete-columns-to-make-sorted
1302-delete-characters-to-make-fancy-string
1557-check-if-a-string-contains-all-binary-codes-of-size-k
1904-second-largest-digit-in-a-string
2346-largest-3-same-digit-number-in-string
2361-calculate-digit-sum-of-a-string
2502-sort-the-people
2536-determine-if-two-events-have-conflict
3312-number-of-changing-keys
3379-score-of-a-string
3396-valid-word
3617-find-the-original-typed-string-i
3684-substring-matching-pattern
3753-maximum-difference-between-even-and-odd-frequency-i

Geometry

0866-rectangle-overlap
1115-valid-boomerang

Bit Manipulation

0067-add-binary
0136-single-number
0190-reverse-bits
0231-power-of-two
0260-single-number-iii
0268-missing-number
0342-power-of-four
0389-find-the-difference
0405-convert-a-number-to-hexadecimal
0476-number-complement
0645-set-mismatch
1054-complement-of-base-10-integer
1557-check-if-a-string-contains-all-binary-codes-of-size-k
1993-sum-of-all-subset-xor-totals
2170-count-number-of-maximum-bitwise-or-subsets
2503-longest-subarray-with-maximum-bitwise-and
3044-minimum-operations-to-collect-elements
3428-find-the-xor-of-numbers-which-appear-twice
3600-find-the-k-th-character-in-string-game-i

Binary Search

0167-two-sum-ii-input-array-is-sorted
0209-minimum-size-subarray-sum
0268-missing-number
0350-intersection-of-two-arrays-ii
0540-single-element-in-a-sorted-array
0658-find-k-closest-elements
0745-find-smallest-letter-greater-than-target
0792-binary-search
2469-longest-subsequence-with-limited-sum
2614-maximum-count-of-positive-integer-and-negative-integer
2634-minimum-common-value
3790-fruits-into-baskets-ii

Sorting

0015-3sum
0018-4sum
0088-merge-sorted-array
0164-maximum-gap
0169-majority-element
0217-contains-duplicate
0229-majority-element-ii
0268-missing-number
0350-intersection-of-two-arrays-ii
0389-find-the-difference
0414-third-maximum-number
0455-assign-cookies
0594-longest-harmonious-subsequence
0645-set-mismatch
0658-find-k-closest-elements
0900-reordered-power-of-2
0941-sort-array-by-parity
0958-sort-array-by-parity-ii
0991-array-of-doubled-pairs
1019-squares-of-a-sorted-array
1217-relative-sort-array
1256-rank-transform-of-an-array
1584-average-salary-excluding-the-minimum-and-maximum-salary
1741-sort-array-by-increasing-frequency
2042-maximum-product-difference-between-two-pairs
2204-find-subsequence-of-length-k-with-the-largest-sum
2387-partition-array-such-that-maximum-difference-is-k
2469-longest-subsequence-with-limited-sum
2497-maximum-matching-of-players-with-trainers
2502-sort-the-people
2524-largest-positive-integer-that-exists-with-its-negative
2561-number-of-distinct-averages
2650-split-with-minimum-sum
2695-find-score-of-an-array-after-marking-all-elements
2756-buy-two-chocolates
2836-neither-minimum-nor-maximum
3241-divide-array-into-arrays-with-max-difference
3263-divide-an-array-into-subarrays-with-minimum-cost-i

Dynamic Programming

0005-longest-palindromic-substring
0053-maximum-subarray
0070-climbing-stairs
0118-pascals-triangle
0121-best-time-to-buy-and-sell-stock
0198-house-robber
0392-is-subsequence
0747-min-cost-climbing-stairs
1013-fibonacci-number
1402-count-square-submatrices-with-all-ones
1586-longest-subarray-of-1s-after-deleting-one-element
1628-count-submatrices-with-all-ones
2267-minimum-difference-in-sums-after-removal-of-elements
3490-find-the-maximum-length-of-valid-subsequence-i

Recursion

0203-remove-linked-list-elements
0206-reverse-linked-list
0231-power-of-two
0326-power-of-three
0342-power-of-four
1013-fibonacci-number
3600-find-the-k-th-character-in-string-game-i

Memoization

0070-climbing-stairs
1013-fibonacci-number

Counting

0169-majority-element
0229-majority-element-ii
0383-ransom-note
0594-longest-harmonious-subsequence
0900-reordered-power-of-2
0920-uncommon-words-from-two-sentences
0950-x-of-a-kind-in-a-deck-of-cards
1510-find-lucky-integer-in-an-array
1635-number-of-good-pairs
2614-maximum-count-of-positive-integer-and-negative-integer
3242-count-elements-with-maximum-frequency
3753-maximum-difference-between-even-and-odd-frequency-i

Greedy

0316-remove-duplicate-letters
0455-assign-cookies
0979-di-string-match
0991-array-of-doubled-pairs
1448-maximum-69-number
1529-max-difference-you-can-get-from-changing-an-integer
2199-two-furthest-houses-with-different-colors
2387-partition-array-such-that-maximum-difference-is-k
2469-longest-subsequence-with-limited-sum
2497-maximum-matching-of-players-with-trainers
2650-split-with-minimum-sum
2756-buy-two-chocolates
3241-divide-array-into-arrays-with-max-difference
3788-maximum-unique-subarray-sum-after-deletion

Backtracking

0017-letter-combinations-of-a-phone-number
1993-sum-of-all-subset-xor-totals
2170-count-number-of-maximum-bitwise-or-subsets

Enumeration

0900-reordered-power-of-2
1010-powerful-integers
1993-sum-of-all-subset-xor-totals
2037-count-square-sum-triples
2122-count-special-quadruplets
2170-count-number-of-maximum-bitwise-or-subsets
2844-sum-of-squares-of-special-elements
3263-divide-an-array-into-subarrays-with-minimum-cost-i
3398-make-a-square-with-the-same-color

String Matching

0028-find-the-index-of-the-first-occurrence-in-a-string
3684-substring-matching-pattern

Trie

0014-longest-common-prefix

Stack

0020-valid-parentheses
0094-binary-tree-inorder-traversal
0316-remove-duplicate-letters
0496-next-greater-element-i
0503-next-greater-element-ii
0682-baseball-game
0739-daily-temperatures
1570-final-prices-with-a-special-discount-in-a-shop
1628-count-submatrices-with-all-ones

Divide and Conquer

0053-maximum-subarray
0169-majority-element
0190-reverse-bits
0395-longest-substring-with-at-least-k-repeating-characters

Heap (Priority Queue)

0658-find-k-closest-elements
2204-find-subsequence-of-length-k-with-the-largest-sum
2267-minimum-difference-in-sums-after-removal-of-elements
2695-find-score-of-an-array-after-marking-all-elements

Sliding Window

0003-longest-substring-without-repeating-characters
0209-minimum-size-subarray-sum
0395-longest-substring-with-at-least-k-repeating-characters
0424-longest-repeating-character-replacement
0438-find-all-anagrams-in-a-string
0594-longest-harmonious-subsequence
0643-maximum-average-subarray-i
0658-find-k-closest-elements
0940-fruit-into-baskets
1586-longest-subarray-of-1s-after-deleting-one-element

Simulation

0067-add-binary
0412-fizz-buzz
0498-diagonal-traverse
0682-baseball-game
2132-convert-1d-array-into-2d-array
2361-calculate-digit-sum-of-a-string
2695-find-score-of-an-array-after-marking-all-elements
3164-last-visited-integers
3311-ant-on-the-boundary
3600-find-the-k-th-character-in-string-game-i
3790-fruits-into-baskets-ii

Combinatorics

1993-sum-of-all-subset-xor-totals

Monotonic Stack

0316-remove-duplicate-letters
0496-next-greater-element-i
0503-next-greater-element-ii
0739-daily-temperatures
1570-final-prices-with-a-special-discount-in-a-shop
1628-count-submatrices-with-all-ones

Tree

0094-binary-tree-inorder-traversal

Depth-First Search

0094-binary-tree-inorder-traversal

Binary Tree

0094-binary-tree-inorder-traversal

Matrix

0498-diagonal-traverse
1402-count-square-submatrices-with-all-ones
1496-lucky-numbers-in-a-matrix
1628-count-submatrices-with-all-ones
1704-special-positions-in-a-binary-matrix
2132-convert-1d-array-into-2d-array
2675-find-the-width-of-columns-of-a-grid
2722-prime-in-diagonal
3398-make-a-square-with-the-same-color

Counting Sort

1217-relative-sort-array

Union Find

0128-longest-consecutive-sequence

Prefix Sum

0209-minimum-size-subarray-sum
2469-longest-subsequence-with-limited-sum
3311-ant-on-the-boundary

Brainteaser

2503-longest-subarray-with-maximum-bitwise-and

Graph

1039-find-the-town-judge

Segment Tree

3790-fruits-into-baskets-ii

Ordered Set

3790-fruits-into-baskets-ii

Rolling Hash

1557-check-if-a-string-contains-all-binary-codes-of-size-k

Hash Function

1557-check-if-a-string-contains-all-binary-codes-of-size-k

Bucket Sort

0164-maximum-gap

Radix Sort

0164-maximum-gap