LeetCode

Collection of LeetCode questions to ace the coding interview! - Created using LeetHub v3

LeetCode Topics

Array

0001-two-sum
0004-median-of-two-sorted-arrays
0015-3sum
0026-remove-duplicates-from-sorted-array
0027-remove-element
0034-find-first-and-last-position-of-element-in-sorted-array
0035-search-insert-position
0036-valid-sudoku
0041-first-missing-positive
0042-trapping-rain-water
0048-rotate-image
0066-plus-one
0073-set-matrix-zeroes
0074-search-a-2d-matrix
0075-sort-colors
0081-search-in-rotated-sorted-array-ii
0088-merge-sorted-array
0108-convert-sorted-array-to-binary-search-tree
0118-pascals-triangle
0119-pascals-triangle-ii
0121-best-time-to-buy-and-sell-stock
0136-single-number
0150-evaluate-reverse-polish-notation
0153-find-minimum-in-rotated-sorted-array
0154-find-minimum-in-rotated-sorted-array-ii
0162-find-peak-element
0164-maximum-gap
0167-two-sum-ii-input-array-is-sorted
0169-majority-element
0189-rotate-array
0204-count-primes
0215-kth-largest-element-in-an-array
0217-contains-duplicate
0219-contains-duplicate-ii
0228-summary-ranges
0229-majority-element-ii
0238-product-of-array-except-self
0240-search-a-2d-matrix-ii
0268-missing-number
0283-move-zeroes
0287-find-the-duplicate-number
0300-longest-increasing-subsequence
0303-range-sum-query-immutable
0304-range-sum-query-2d-immutable
0334-increasing-triplet-subsequence
0349-intersection-of-two-arrays
0350-intersection-of-two-arrays-ii
0414-third-maximum-number
0448-find-all-numbers-disappeared-in-an-array
0456-132-pattern
0485-max-consecutive-ones
0495-teemo-attacking
0500-keyboard-row
0506-relative-ranks
0561-array-partition
0575-distribute-candies
0599-minimum-index-sum-of-two-lists
0605-can-place-flowers
0628-maximum-product-of-three-numbers
0643-maximum-average-subarray-i
0645-set-mismatch
0674-longest-continuous-increasing-subsequence
0682-baseball-game
0697-degree-of-an-array
0717-1-bit-and-2-bit-characters
0745-find-smallest-letter-greater-than-target
0748-largest-number-at-least-twice-of-others
0749-shortest-completing-word
0777-toeplitz-matrix
0792-binary-search
0816-design-hashset
0817-design-hashmap
0822-unique-morse-code-words
0824-number-of-lines-to-write-string
0837-most-common-word
0860-design-circular-queue
0861-flipping-an-image
0898-transpose-matrix
0932-monotonic-array
0941-sort-array-by-parity
0944-smallest-range-i
0948-sort-an-array
0965-unique-email-addresses
0981-delete-columns-to-make-sorted
1001-n-repeated-element-in-size-2n-array
1006-vowel-spellchecker
1018-largest-perimeter-triangle
1019-squares-of-a-sorted-array
1031-add-to-array-form-of-integer
1041-available-captures-for-rook
1044-find-common-characters
1071-binary-prefix-divisible-by-5
1112-find-words-that-can-be-formed-by-characters
1137-height-checker
1221-element-appearing-more-than-25-in-sorted-array
1227-number-of-equivalent-domino-pairs
1231-replace-elements-with-greatest-element-on-right-side
1287-distance-between-bus-stops
1293-three-consecutive-odds
1306-minimum-absolute-difference
1319-unique-number-of-occurrences
1349-check-if-it-is-a-straight-line
1378-cells-with-odd-values-in-a-matrix
1386-shift-2d-grid
1392-find-the-difference-of-two-arrays
1421-find-numbers-with-even-number-of-digits
1463-the-k-weakest-rows-in-a-matrix
1468-check-if-n-and-its-double-exist
1476-count-negative-numbers-in-a-sorted-matrix
1482-how-many-numbers-are-smaller-than-the-current-number
1486-find-the-distance-value-between-two-arrays
1496-lucky-numbers-in-a-matrix
1505-create-target-array-in-the-given-order
1510-find-lucky-integer-in-an-array
1528-kids-with-the-greatest-number-of-candies
1548-check-if-all-1s-are-at-least-length-k-places-away
1556-make-two-arrays-equal-by-reversing-subarrays
1560-number-of-students-doing-homework-at-a-given-time
1570-final-prices-with-a-special-discount-in-a-shop
1574-maximum-product-of-two-elements-in-an-array
1580-shuffle-the-array
1584-average-salary-excluding-the-minimum-and-maximum-salary
1603-running-sum-of-1d-array
1615-range-sum-of-sorted-subarray-sums
1626-can-make-arithmetic-progression-from-sequence
1635-number-of-good-pairs
1646-kth-missing-positive-number
1651-shuffle-string
1656-count-good-triplets
1677-matrix-diagonal-sum
1791-richest-customer-wealth
1833-find-the-highest-altitude
1927-maximum-ascending-subarray-sum
1950-sign-of-the-product-of-an-array
1951-find-the-winner-of-the-circular-game
2048-build-array-from-permutation
2058-concatenation-of-array
2132-convert-1d-array-into-2d-array
2137-final-value-of-variable-after-performing-operations
2144-maximum-difference-between-increasing-elements
2190-count-common-words-with-one-occurrence
2210-find-target-indices-after-sorting-array
2219-maximum-number-of-words-found-in-sentences
2231-find-first-palindromic-string-in-the-array
2232-adding-spaces-to-a-string
2277-count-equal-and-divisible-pairs-in-an-array
2307-replace-non-coprime-numbers-in-array
2338-minimum-consecutive-cards-to-pick-up
2524-largest-positive-integer-that-exists-with-its-negative
2551-apply-operations-to-an-array
2614-maximum-count-of-positive-integer-and-negative-integer
2691-count-vowel-strings-in-ranges
2722-prime-in-diagonal
2727-number-of-senior-citizens
3194-find-words-containing-character
3242-count-elements-with-maximum-frequency
3251-maximum-area-of-longest-diagonal-rectangle
3321-type-of-triangle
3427-special-array-ii
3429-special-array-i
3476-find-minimum-operations-to-make-all-elements-divisible-by-three
3555-final-array-state-after-k-multiplication-operations-i
3581-the-two-sneaky-numbers-of-digitville
3606-minimum-element-after-replacement-with-digit-sum
3651-transformed-array
3685-count-subarrays-of-length-three-with-a-condition
3704-count-partitions-with-even-sum-difference
3731-sum-of-variable-length-subarrays
3747-maximum-difference-between-adjacent-elements-in-a-circular-array
3748-sort-matrix-by-diagonals
3778-transform-array-by-parity
3788-maximum-unique-subarray-sum-after-deletion
3827-implement-router
3832-minimum-cost-to-reach-every-position
3846-minimum-operations-to-make-array-sum-divisible-by-k
3869-smallest-index-with-digit-sum-equal-to-index
3914-check-if-any-element-has-prime-frequency
3934-coupon-code-validator
3965-earliest-finish-time-for-land-and-water-rides-i
3967-earliest-finish-time-for-land-and-water-rides-ii

Hash Table

0001-two-sum
0003-longest-substring-without-repeating-characters
0013-roman-to-integer
0036-valid-sudoku
0041-first-missing-positive
0073-set-matrix-zeroes
0141-linked-list-cycle
0160-intersection-of-two-linked-lists
0169-majority-element
0202-happy-number
0205-isomorphic-strings
0217-contains-duplicate
0219-contains-duplicate-ii
0229-majority-element-ii
0242-valid-anagram
0268-missing-number
0290-word-pattern
0349-intersection-of-two-arrays
0350-intersection-of-two-arrays-ii
0387-first-unique-character-in-a-string
0389-find-the-difference
0409-longest-palindrome
0448-find-all-numbers-disappeared-in-an-array
0500-keyboard-row
0575-distribute-candies
0599-minimum-index-sum-of-two-lists
0645-set-mismatch
0653-two-sum-iv-input-is-a-bst
0697-degree-of-an-array
0749-shortest-completing-word
0782-jewels-and-stones
0816-design-hashset
0817-design-hashmap
0822-unique-morse-code-words
0837-most-common-word
0920-uncommon-words-from-two-sentences
0965-unique-email-addresses
1001-n-repeated-element-in-size-2n-array
1006-vowel-spellchecker
1044-find-common-characters
1112-find-words-that-can-be-formed-by-characters
1227-number-of-equivalent-domino-pairs
1264-maximum-number-of-words-you-can-type
1297-maximum-number-of-balloons
1319-unique-number-of-occurrences
1392-find-the-difference-of-two-arrays
1468-check-if-n-and-its-double-exist
1482-how-many-numbers-are-smaller-than-the-current-number
1510-find-lucky-integer-in-an-array
1556-make-two-arrays-equal-by-reversing-subarrays
1635-number-of-good-pairs
2177-check-whether-two-strings-are-almost-equivalent
2190-count-common-words-with-one-occurrence
2226-rings-and-rods
2338-minimum-consecutive-cards-to-pick-up
2524-largest-positive-integer-that-exists-with-its-negative
2778-frequency-tracker
3242-count-elements-with-maximum-frequency
3353-existence-of-a-substring-in-a-string-and-its-reverse
3581-the-two-sneaky-numbers-of-digitville
3788-maximum-unique-subarray-sum-after-deletion
3827-implement-router
3871-minimum-deletions-for-at-most-k-distinct-characters
3872-find-most-frequent-vowel-and-consonant
3914-check-if-any-element-has-prime-frequency
3934-coupon-code-validator

Linked List

0002-add-two-numbers
0019-remove-nth-node-from-end-of-list
0021-merge-two-sorted-lists
0023-merge-k-sorted-lists
0024-swap-nodes-in-pairs
0025-reverse-nodes-in-k-group
0082-remove-duplicates-from-sorted-list-ii
0083-remove-duplicates-from-sorted-list
0141-linked-list-cycle
0148-sort-list
0160-intersection-of-two-linked-lists
0203-remove-linked-list-elements
0206-reverse-linked-list
0234-palindrome-linked-list
0237-delete-node-in-a-linked-list
0328-odd-even-linked-list
0445-add-two-numbers-ii
0816-design-hashset
0817-design-hashmap
0860-design-circular-queue
0908-middle-of-the-linked-list
1411-convert-binary-number-in-a-linked-list-to-integer
2216-delete-the-middle-node-of-a-linked-list
2236-maximum-twin-sum-of-a-linked-list

Math

0002-add-two-numbers
0007-reverse-integer
0009-palindrome-number
0013-roman-to-integer
0029-divide-two-integers
0043-multiply-strings
0048-rotate-image
0050-powx-n
0066-plus-one
0067-add-binary
0069-sqrtx
0070-climbing-stairs
0150-evaluate-reverse-polish-notation
0168-excel-sheet-column-title
0171-excel-sheet-column-number
0172-factorial-trailing-zeroes
0189-rotate-array
0202-happy-number
0204-count-primes
0231-power-of-two
0258-add-digits
0268-missing-number
0319-bulb-switcher
0371-sum-of-two-integers
0405-convert-a-number-to-hexadecimal
0412-fizz-buzz
0415-add-strings
0445-add-two-numbers-ii
0504-base-7
0507-perfect-number
0628-maximum-product-of-three-numbers
0944-smallest-range-i
1013-fibonacci-number
1018-largest-perimeter-triangle
1031-add-to-array-form-of-integer
1086-divisor-game
1146-greatest-common-divisor-of-strings
1260-day-of-the-year
1274-number-of-days-between-two-dates
1349-check-if-it-is-a-straight-line
1378-cells-with-odd-values-in-a-matrix
1411-convert-binary-number-in-a-linked-list-to-integer
1421-find-numbers-with-even-number-of-digits
1501-circle-and-rectangle-overlapping
1529-max-difference-you-can-get-from-changing-an-integer
1630-count-odd-numbers-in-an-interval-range
1635-number-of-good-pairs
1950-sign-of-the-product-of-an-array
1951-find-the-winner-of-the-circular-game
2284-smallest-value-of-the-rearranged-number
2307-replace-non-coprime-numbers-in-array
2383-add-two-integers
2645-pass-the-pillow
2722-prime-in-diagonal
3172-divisible-and-non-divisible-sums-difference
3321-type-of-triangle
3462-vowels-game-in-a-string
3476-find-minimum-operations-to-make-all-elements-divisible-by-three
3555-final-array-state-after-k-multiplication-operations-i
3567-convert-date-to-binary
3581-the-two-sneaky-numbers-of-digitville
3606-minimum-element-after-replacement-with-digit-sum
3704-count-partitions-with-even-sum-difference
3768-check-if-digits-are-equal-in-string-after-operations-i
3830-find-closest-person
3846-minimum-operations-to-make-array-sum-divisible-by-k
3869-smallest-index-with-digit-sum-equal-to-index
3912-hexadecimal-and-hexatrigesimal-conversion
3914-check-if-any-element-has-prime-frequency

Recursion

0002-add-two-numbers
0021-merge-two-sorted-lists
0024-swap-nodes-in-pairs
0025-reverse-nodes-in-k-group
0050-powx-n
0203-remove-linked-list-elements
0206-reverse-linked-list
0231-power-of-two
0234-palindrome-linked-list
1013-fibonacci-number
1951-find-the-winner-of-the-circular-game

String

0003-longest-substring-without-repeating-characters
0005-longest-palindromic-substring
0008-string-to-integer-atoi
0013-roman-to-integer
0020-valid-parentheses
0028-find-the-index-of-the-first-occurrence-in-a-string
0043-multiply-strings
0058-length-of-last-word
0067-add-binary
0125-valid-palindrome
0151-reverse-words-in-a-string
0168-excel-sheet-column-title
0171-excel-sheet-column-number
0205-isomorphic-strings
0242-valid-anagram
0257-binary-tree-paths
0290-word-pattern
0344-reverse-string
0345-reverse-vowels-of-a-string
0387-first-unique-character-in-a-string
0389-find-the-difference
0392-is-subsequence
0405-convert-a-number-to-hexadecimal
0409-longest-palindrome
0412-fizz-buzz
0415-add-strings
0443-string-compression
0482-license-key-formatting
0500-keyboard-row
0504-base-7
0520-detect-capital
0541-reverse-string-ii
0551-student-attendance-record-i
0557-reverse-words-in-a-string-iii
0599-minimum-index-sum-of-two-lists
0657-robot-return-to-origin
0680-valid-palindrome-ii
0742-to-lower-case
0749-shortest-completing-word
0782-jewels-and-stones
0812-rotate-string
0822-unique-morse-code-words
0824-number-of-lines-to-write-string
0837-most-common-word
0851-goat-latin
0874-backspace-string-compare
0920-uncommon-words-from-two-sentences
0953-reverse-only-letters
0961-long-pressed-name
0965-unique-email-addresses
0981-delete-columns-to-make-sorted
1006-vowel-spellchecker
1044-find-common-characters
1078-remove-outermost-parentheses
1112-find-words-that-can-be-formed-by-characters
1128-remove-all-adjacent-duplicates-in-string
1146-greatest-common-divisor-of-strings
1156-occurrences-after-bigram
1205-defanging-an-ip-address
1260-day-of-the-year
1264-maximum-number-of-words-you-can-type
1274-number-of-days-between-two-dates
1283-reformat-date
1297-maximum-number-of-balloons
1341-split-a-string-in-balanced-strings
1537-maximum-score-after-splitting-a-string
1542-consecutive-characters
1566-check-if-a-word-occurs-as-a-prefix-of-any-word-in-a-sentence
1651-shuffle-string
1797-goal-parser-interpretation
1807-partitioning-into-minimum-number-of-deci-binary-numbers
1894-merge-strings-alternately
2021-remove-all-occurrences-of-a-substring
2137-final-value-of-variable-after-performing-operations
2154-minimum-moves-to-convert-string
2177-check-whether-two-strings-are-almost-equivalent
2190-count-common-words-with-one-occurrence
2219-maximum-number-of-words-found-in-sentences
2226-rings-and-rods
2231-find-first-palindromic-string-in-the-array
2232-adding-spaces-to-a-string
2235-capitalize-the-title
2260-divide-a-string-into-groups-of-size-k
2337-remove-digit-from-number-to-maximize-result
2470-removing-stars-from-a-string
2691-count-vowel-strings-in-ranges
2727-number-of-senior-citizens
2887-sort-vowels-in-a-string
3194-find-words-containing-character
3353-existence-of-a-substring-in-a-string-and-its-reverse
3379-score-of-a-string
3462-vowels-game-in-a-string
3567-convert-date-to-binary
3636-check-balanced-string
3768-check-if-digits-are-equal-in-string-after-operations-i
3811-reverse-degree-of-a-string
3871-minimum-deletions-for-at-most-k-distinct-characters
3872-find-most-frequent-vowel-and-consonant
3893-generate-tag-for-video-caption
3912-hexadecimal-and-hexatrigesimal-conversion
3934-coupon-code-validator

Sliding Window

0003-longest-substring-without-repeating-characters
0219-contains-duplicate-ii
0643-maximum-average-subarray-i
2338-minimum-consecutive-cards-to-pick-up

Binary Search

0004-median-of-two-sorted-arrays
0034-find-first-and-last-position-of-element-in-sorted-array
0035-search-insert-position
0069-sqrtx
0074-search-a-2d-matrix
0081-search-in-rotated-sorted-array-ii
0153-find-minimum-in-rotated-sorted-array
0154-find-minimum-in-rotated-sorted-array-ii
0162-find-peak-element
0167-two-sum-ii-input-array-is-sorted
0240-search-a-2d-matrix-ii
0268-missing-number
0287-find-the-duplicate-number
0300-longest-increasing-subsequence
0349-intersection-of-two-arrays
0350-intersection-of-two-arrays-ii
0456-132-pattern
0745-find-smallest-letter-greater-than-target
0792-binary-search
1463-the-k-weakest-rows-in-a-matrix
1468-check-if-n-and-its-double-exist
1476-count-negative-numbers-in-a-sorted-matrix
1486-find-the-distance-value-between-two-arrays
1615-range-sum-of-sorted-subarray-sums
1646-kth-missing-positive-number
2210-find-target-indices-after-sorting-array
2614-maximum-count-of-positive-integer-and-negative-integer
3427-special-array-ii
3827-implement-router
3965-earliest-finish-time-for-land-and-water-rides-i
3967-earliest-finish-time-for-land-and-water-rides-ii

Divide and Conquer

0004-median-of-two-sorted-arrays
0023-merge-k-sorted-lists
0108-convert-sorted-array-to-binary-search-tree
0148-sort-list
0169-majority-element
0190-reverse-bits
0191-number-of-1-bits
0215-kth-largest-element-in-an-array
0240-search-a-2d-matrix-ii
0948-sort-an-array

Two Pointers

0005-longest-palindromic-substring
0015-3sum
0019-remove-nth-node-from-end-of-list
0026-remove-duplicates-from-sorted-array
0027-remove-element
0028-find-the-index-of-the-first-occurrence-in-a-string
0042-trapping-rain-water
0075-sort-colors
0082-remove-duplicates-from-sorted-list-ii
0088-merge-sorted-array
0125-valid-palindrome
0141-linked-list-cycle
0148-sort-list
0151-reverse-words-in-a-string
0160-intersection-of-two-linked-lists
0167-two-sum-ii-input-array-is-sorted
0189-rotate-array
0202-happy-number
0234-palindrome-linked-list
0283-move-zeroes
0287-find-the-duplicate-number
0344-reverse-string
0345-reverse-vowels-of-a-string
0349-intersection-of-two-arrays
0350-intersection-of-two-arrays-ii
0392-is-subsequence
0443-string-compression
0541-reverse-string-ii
0557-reverse-words-in-a-string-iii
0653-two-sum-iv-input-is-a-bst
0680-valid-palindrome-ii
0861-flipping-an-image
0874-backspace-string-compare
0908-middle-of-the-linked-list
0941-sort-array-by-parity
0953-reverse-only-letters
0961-long-pressed-name
1019-squares-of-a-sorted-array
1468-check-if-n-and-its-double-exist
1486-find-the-distance-value-between-two-arrays
1566-check-if-a-word-occurs-as-a-prefix-of-any-word-in-a-sentence
1615-range-sum-of-sorted-subarray-sums
1894-merge-strings-alternately
2216-delete-the-middle-node-of-a-linked-list
2231-find-first-palindromic-string-in-the-array
2232-adding-spaces-to-a-string
2236-maximum-twin-sum-of-a-linked-list
2524-largest-positive-integer-that-exists-with-its-negative
2551-apply-operations-to-an-array
3965-earliest-finish-time-for-land-and-water-rides-i
3967-earliest-finish-time-for-land-and-water-rides-ii

Dynamic Programming

0005-longest-palindromic-substring
0042-trapping-rain-water
0070-climbing-stairs
0118-pascals-triangle
0119-pascals-triangle-ii
0121-best-time-to-buy-and-sell-stock
0300-longest-increasing-subsequence
0338-counting-bits
0392-is-subsequence
1013-fibonacci-number
1086-divisor-game

Sorting

0015-3sum
0075-sort-colors
0088-merge-sorted-array
0148-sort-list
0164-maximum-gap
0169-majority-element
0215-kth-largest-element-in-an-array
0217-contains-duplicate
0229-majority-element-ii
0242-valid-anagram
0268-missing-number
0349-intersection-of-two-arrays
0350-intersection-of-two-arrays-ii
0389-find-the-difference
0414-third-maximum-number
0506-relative-ranks
0561-array-partition
0628-maximum-product-of-three-numbers
0645-set-mismatch
0748-largest-number-at-least-twice-of-others
0941-sort-array-by-parity
0948-sort-an-array
1018-largest-perimeter-triangle
1019-squares-of-a-sorted-array
1137-height-checker
1306-minimum-absolute-difference
1463-the-k-weakest-rows-in-a-matrix
1468-check-if-n-and-its-double-exist
1482-how-many-numbers-are-smaller-than-the-current-number
1486-find-the-distance-value-between-two-arrays
1556-make-two-arrays-equal-by-reversing-subarrays
1574-maximum-product-of-two-elements-in-an-array
1584-average-salary-excluding-the-minimum-and-maximum-salary
1615-range-sum-of-sorted-subarray-sums
1626-can-make-arithmetic-progression-from-sequence
2210-find-target-indices-after-sorting-array
2284-smallest-value-of-the-rearranged-number
2524-largest-positive-integer-that-exists-with-its-negative
2887-sort-vowels-in-a-string
3321-type-of-triangle
3748-sort-matrix-by-diagonals
3778-transform-array-by-parity
3871-minimum-deletions-for-at-most-k-distinct-characters
3934-coupon-code-validator
3965-earliest-finish-time-for-land-and-water-rides-i
3967-earliest-finish-time-for-land-and-water-rides-ii

Stack

0020-valid-parentheses
0042-trapping-rain-water
0094-binary-tree-inorder-traversal
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0150-evaluate-reverse-polish-notation
0155-min-stack
0225-implement-stack-using-queues
0232-implement-queue-using-stacks
0234-palindrome-linked-list
0445-add-two-numbers-ii
0456-132-pattern
0682-baseball-game
0776-n-ary-tree-postorder-traversal
0874-backspace-string-compare
0933-increasing-order-search-tree
1078-remove-outermost-parentheses
1128-remove-all-adjacent-duplicates-in-string
1570-final-prices-with-a-special-discount-in-a-shop
2021-remove-all-occurrences-of-a-substring
2236-maximum-twin-sum-of-a-linked-list
2307-replace-non-coprime-numbers-in-array
2470-removing-stars-from-a-string

Heap (Priority Queue)

0023-merge-k-sorted-lists
0215-kth-largest-element-in-an-array
0506-relative-ranks
0948-sort-an-array
1463-the-k-weakest-rows-in-a-matrix
1574-maximum-product-of-two-elements-in-an-array
3555-final-array-state-after-k-multiplication-operations-i

Merge Sort

0023-merge-k-sorted-lists
0148-sort-list
0948-sort-an-array

String Matching

0028-find-the-index-of-the-first-occurrence-in-a-string
0812-rotate-string
1566-check-if-a-word-occurs-as-a-prefix-of-any-word-in-a-sentence

Bit Manipulation

0029-divide-two-integers
0067-add-binary
0136-single-number
0190-reverse-bits
0191-number-of-1-bits
0231-power-of-two
0268-missing-number
0287-find-the-duplicate-number
0338-counting-bits
0371-sum-of-two-integers
0389-find-the-difference
0405-convert-a-number-to-hexadecimal
0645-set-mismatch
0861-flipping-an-image
1071-binary-prefix-divisible-by-5

Matrix

0036-valid-sudoku
0048-rotate-image
0073-set-matrix-zeroes
0074-search-a-2d-matrix
0240-search-a-2d-matrix-ii
0304-range-sum-query-2d-immutable
0777-toeplitz-matrix
0861-flipping-an-image
0898-transpose-matrix
1041-available-captures-for-rook
1386-shift-2d-grid
1463-the-k-weakest-rows-in-a-matrix
1476-count-negative-numbers-in-a-sorted-matrix
1496-lucky-numbers-in-a-matrix
1677-matrix-diagonal-sum
1791-richest-customer-wealth
2132-convert-1d-array-into-2d-array
2722-prime-in-diagonal
3748-sort-matrix-by-diagonals

Monotonic Stack

0042-trapping-rain-water
0456-132-pattern
1570-final-prices-with-a-special-discount-in-a-shop

Simulation

0043-multiply-strings
0067-add-binary
0258-add-digits
0412-fizz-buzz
0415-add-strings
0495-teemo-attacking
0657-robot-return-to-origin
0682-baseball-game
0861-flipping-an-image
0874-backspace-string-compare
0898-transpose-matrix
1041-available-captures-for-rook
1378-cells-with-odd-values-in-a-matrix
1386-shift-2d-grid
1505-create-target-array-in-the-given-order
1951-find-the-winner-of-the-circular-game
2021-remove-all-occurrences-of-a-substring
2048-build-array-from-permutation
2058-concatenation-of-array
2132-convert-1d-array-into-2d-array
2137-final-value-of-variable-after-performing-operations
2232-adding-spaces-to-a-string
2260-divide-a-string-into-groups-of-size-k
2470-removing-stars-from-a-string
2551-apply-operations-to-an-array
2645-pass-the-pillow
3555-final-array-state-after-k-multiplication-operations-i
3651-transformed-array
3768-check-if-digits-are-equal-in-string-after-operations-i
3811-reverse-degree-of-a-string
3893-generate-tag-for-video-caption

Memoization

0070-climbing-stairs
1013-fibonacci-number

Design

0155-min-stack
0225-implement-stack-using-queues
0232-implement-queue-using-stacks
0303-range-sum-query-immutable
0304-range-sum-query-2d-immutable
0816-design-hashset
0817-design-hashmap
0860-design-circular-queue
2778-frequency-tracker
3827-implement-router

Bucket Sort

0164-maximum-gap
0948-sort-an-array

Radix Sort

0164-maximum-gap
0948-sort-an-array

Counting

0169-majority-element
0229-majority-element-ii
0387-first-unique-character-in-a-string
0837-most-common-word
0920-uncommon-words-from-two-sentences
1112-find-words-that-can-be-formed-by-characters
1227-number-of-equivalent-domino-pairs
1297-maximum-number-of-balloons
1341-split-a-string-in-balanced-strings
1510-find-lucky-integer-in-an-array
1635-number-of-good-pairs
2177-check-whether-two-strings-are-almost-equivalent
2190-count-common-words-with-one-occurrence
2614-maximum-count-of-positive-integer-and-negative-integer
3242-count-elements-with-maximum-frequency
3778-transform-array-by-parity
3871-minimum-deletions-for-at-most-k-distinct-characters
3872-find-most-frequent-vowel-and-consonant
3914-check-if-any-element-has-prime-frequency

Database

0175-combine-two-tables
0176-second-highest-salary
0197-rising-temperature
0584-find-customer-referee
0595-big-countries
1153-product-sales-analysis-i
1258-article-views-i
1509-replace-employee-id-with-the-unique-identifier
1724-customer-who-visited-but-did-not-make-any-transactions
1827-invalid-tweets
1908-recyclable-and-low-fat-products

Enumeration

0204-count-primes
1656-count-good-triplets
2337-remove-digit-from-number-to-maximize-result

Number Theory

0204-count-primes
0258-add-digits
2307-replace-non-coprime-numbers-in-array
2722-prime-in-diagonal
3768-check-if-digits-are-equal-in-string-after-operations-i
3914-check-if-any-element-has-prime-frequency

Quickselect

0215-kth-largest-element-in-an-array

Queue

0225-implement-stack-using-queues
0232-implement-queue-using-stacks
0387-first-unique-character-in-a-string
0860-design-circular-queue
1951-find-the-winner-of-the-circular-game
3827-implement-router

Prefix Sum

0238-product-of-array-except-self
0303-range-sum-query-immutable
0304-range-sum-query-2d-immutable
1537-maximum-score-after-splitting-a-string
1603-running-sum-of-1d-array
1615-range-sum-of-sorted-subarray-sums
1833-find-the-highest-altitude
2691-count-vowel-strings-in-ranges
3427-special-array-ii
3704-count-partitions-with-even-sum-difference
3731-sum-of-variable-length-subarrays

Greedy

0334-increasing-triplet-subsequence
0409-longest-palindrome
0561-array-partition
0605-can-place-flowers
0680-valid-palindrome-ii
1018-largest-perimeter-triangle
1341-split-a-string-in-balanced-strings
1529-max-difference-you-can-get-from-changing-an-integer
1807-partitioning-into-minimum-number-of-deci-binary-numbers
2154-minimum-moves-to-convert-string
2337-remove-digit-from-number-to-maximize-result
3788-maximum-unique-subarray-sum-after-deletion
3871-minimum-deletions-for-at-most-k-distinct-characters
3965-earliest-finish-time-for-land-and-water-rides-i
3967-earliest-finish-time-for-land-and-water-rides-ii

Ordered Set

0456-132-pattern
3827-implement-router

Counting Sort

0561-array-partition
0948-sort-an-array
1137-height-checker
1482-how-many-numbers-are-smaller-than-the-current-number

Hash Function

0816-design-hashset
0817-design-hashmap

Brainteaser

0319-bulb-switcher
1086-divisor-game
3462-vowels-game-in-a-string

Game Theory

1086-divisor-game
3462-vowels-game-in-a-string

Geometry

1349-check-if-it-is-a-straight-line
1501-circle-and-rectangle-overlapping

Tree

0094-binary-tree-inorder-traversal
0100-same-tree
0104-maximum-depth-of-binary-tree
0108-convert-sorted-array-to-binary-search-tree
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0257-binary-tree-paths
0653-two-sum-iv-input-is-a-bst
0776-n-ary-tree-postorder-traversal
0933-increasing-order-search-tree

Binary Search Tree

0108-convert-sorted-array-to-binary-search-tree
0653-two-sum-iv-input-is-a-bst
0933-increasing-order-search-tree

Binary Tree

0094-binary-tree-inorder-traversal
0100-same-tree
0104-maximum-depth-of-binary-tree
0108-convert-sorted-array-to-binary-search-tree
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0257-binary-tree-paths
0653-two-sum-iv-input-is-a-bst
0933-increasing-order-search-tree

Depth-First Search

0094-binary-tree-inorder-traversal
0100-same-tree
0104-maximum-depth-of-binary-tree
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0257-binary-tree-paths
0653-two-sum-iv-input-is-a-bst
0776-n-ary-tree-postorder-traversal
0933-increasing-order-search-tree

Backtracking

0257-binary-tree-paths

Breadth-First Search

0100-same-tree
0104-maximum-depth-of-binary-tree
0653-two-sum-iv-input-is-a-bst

Combinatorics

3768-check-if-digits-are-equal-in-string-after-operations-i