Algorithm

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

Array

0001-two-sum
0026-remove-duplicates-from-sorted-array
0027-remove-element
0035-search-insert-position
0066-plus-one

Hash Table

0001-two-sum
0013-roman-to-integer

Math

0009-palindrome-number
0013-roman-to-integer
0066-plus-one

String

0013-roman-to-integer
0014-longest-common-prefix
0020-valid-parentheses
0028-find-the-index-of-the-first-occurrence-in-a-string

Trie

0014-longest-common-prefix

Stack

0020-valid-parentheses

Two Pointers

0026-remove-duplicates-from-sorted-array
0027-remove-element
0028-find-the-index-of-the-first-occurrence-in-a-string

String Matching

0028-find-the-index-of-the-first-occurrence-in-a-string
0058-length-of-last-word

Binary Search

0035-search-insert-position

LeetCode Topics

Math

0002-add-two-numbers
0067-add-binary
0069-sqrtx
0070-climbing-stairs
0258-add-digits
0268-missing-number
0412-fizz-buzz
0509-fibonacci-number
0728-self-dividing-numbers
1146-greatest-common-divisor-of-strings
1295-find-numbers-with-even-number-of-digits
1304-find-n-unique-integers-sum-up-to-zero
1323-maximum-69-number
1342-number-of-steps-to-reduce-a-number-to-zero
1395-minimum-time-visiting-all-points
1399-count-largest-group
1406-subtract-the-product-and-sum-of-digits-of-an-integer
1486-xor-operation-in-an-array
1635-number-of-good-pairs
1693-sum-of-all-odd-length-subarrays
1716-calculate-money-in-leetcode-bank
1742-maximum-number-of-balls-in-a-box
1806-count-of-matches-in-tournament
1812-determine-color-of-a-chessboard-square
1822-sign-of-the-product-of-an-array
1837-sum-of-digits-in-base-k
1889-check-if-number-is-a-sum-of-powers-of-three
1925-count-square-sum-triples
1952-three-divisors
1979-find-greatest-common-divisor-of-array
1993-sum-of-all-subset-xor-totals
2119-a-number-after-a-double-reversal
2125-number-of-laser-beams-in-a-bank
2169-count-operations-to-obtain-zero
2180-count-integers-with-even-digit-sum
2264-minimum-sum-of-four-digit-number-after-splitting-digits
2383-add-two-integers
2396-strictly-palindromic-number
2427-number-of-common-factors
2491-smallest-even-multiple
2520-count-the-digits-that-divide-a-number
2535-difference-between-element-sum-and-digit-sum-of-an-array
2544-alternating-digit-sum
2556-convert-the-temperature
2571-find-the-pivot-integer
2651-calculate-delayed-arrival-time
2752-sum-multiples
2812-find-the-maximum-achievable-number
2843-count-symmetric-integers
3055-maximum-odd-binary-number
3079-find-the-sum-of-encrypted-integers
3172-divisible-and-non-divisible-sums-difference
3227-find-missing-and-repeated-values
3232-find-if-digit-game-can-be-won
3264-final-array-state-after-k-multiplication-operations-i
3270-find-the-key-of-the-numbers
3274-check-if-two-chessboard-squares-have-the-same-color
3300-minimum-element-after-replacement-with-digit-sum
3304-find-the-k-th-character-in-string-game-i
3345-smallest-divisible-digit-product-i
3370-smallest-number-with-all-set-bits
3371-harshad-number
3432-count-partitions-with-even-sum-difference
3476-find-minimum-operations-to-make-all-elements-divisible-by-three
3492-maximum-containers-on-a-ship
3512-minimum-operations-to-make-array-sum-divisible-by-k
3536-maximum-product-of-two-digits
3550-smallest-index-with-digit-sum-equal-to-index
3567-convert-date-to-binary
3581-the-two-sneaky-numbers-of-digitville
3622-check-divisibility-by-digit-sum-and-product
3658-gcd-of-odd-and-even-sums
3663-find-the-least-frequent-digit
3697-compute-decimal-representation
3726-remove-zeros-in-decimal-representation
3736-minimum-moves-to-equal-array-elements-iii
3750-minimum-number-of-flips-to-reverse-binary-string
3768-check-if-digits-are-equal-in-string-after-operations-i
3783-mirror-distance-of-an-integer
3830-find-closest-person

Binary Search

0069-sqrtx
0268-missing-number
0349-intersection-of-two-arrays
2210-find-target-indices-after-sorting-array
2389-longest-subsequence-with-limited-sum
2529-maximum-count-of-positive-integer-and-negative-integer
2824-count-pairs-whose-sum-is-less-than-target

Linked List

0002-add-two-numbers
0021-merge-two-sorted-lists
0083-remove-duplicates-from-sorted-list
0141-linked-list-cycle

Recursion

0002-add-two-numbers
0021-merge-two-sorted-lists
0509-fibonacci-number
3304-find-the-k-th-character-in-string-game-i

Array

0001-two-sum
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
0169-majority-element
0217-contains-duplicate
0238-product-of-array-except-self
0268-missing-number
0283-move-zeroes
0334-increasing-triplet-subsequence
0349-intersection-of-two-arrays
0448-find-all-numbers-disappeared-in-an-array
0485-max-consecutive-ones
0496-next-greater-element-i
0500-keyboard-row
0506-relative-ranks
0561-array-partition
0594-longest-harmonious-subsequence
0605-can-place-flowers
0643-maximum-average-subarray-i
0682-baseball-game
0724-find-pivot-index
0804-unique-morse-code-words
0806-number-of-lines-to-write-string
0861-flipping-an-image
0905-sort-array-by-parity
0942-di-string-match
0944-delete-columns-to-make-sorted
0977-squares-of-a-sorted-array
1002-find-common-characters
1051-height-checker
1122-relative-sort-array
1200-minimum-absolute-difference
1295-find-numbers-with-even-number-of-digits
1304-find-n-unique-integers-sum-up-to-zero
1313-decompress-run-length-encoded-list
1319-unique-number-of-occurrences
1356-sort-integers-by-the-number-of-1-bits
1392-find-the-difference-of-two-arrays
1394-find-lucky-integer-in-an-array
1395-minimum-time-visiting-all-points
1408-string-matching-in-an-array
1436-destination-city
1450-number-of-students-doing-homework-at-a-given-time
1460-make-two-arrays-equal-by-reversing-subarrays
1482-how-many-numbers-are-smaller-than-the-current-number
1491-average-salary-excluding-the-minimum-and-maximum-salary
1502-can-make-arithmetic-progression-from-sequence
1505-create-target-array-in-the-given-order
1528-kids-with-the-greatest-number-of-candies
1534-count-good-triplets
1550-three-consecutive-odds
1570-final-prices-with-a-special-discount-in-a-shop
1574-maximum-product-of-two-elements-in-an-array
1580-shuffle-the-array
1598-crawler-log-folder
1603-running-sum-of-1d-array
1635-number-of-good-pairs
1636-sort-array-by-increasing-frequency
1637-widest-vertical-area-between-two-points-containing-no-points
1651-shuffle-string
1677-matrix-diagonal-sum
1693-sum-of-all-odd-length-subarrays
1710-maximum-units-on-a-truck
1720-decode-xored-array
1725-number-of-rectangles-that-can-form-the-largest-square
1748-sum-of-unique-elements
1773-count-items-matching-a-rule
1781-check-if-two-string-arrays-are-equivalent
1786-count-the-number-of-consistent-strings
1791-richest-customer-wealth
1822-sign-of-the-product-of-an-array
1827-minimum-operations-to-make-the-array-increasing
1833-find-the-highest-altitude
1854-maximum-population-year
1944-truncate-sentence
1979-find-greatest-common-divisor-of-array
1991-find-the-middle-index-in-array
1993-sum-of-all-subset-xor-totals
2006-count-number-of-pairs-with-absolute-difference-k
2032-two-out-of-three
2037-minimum-number-of-moves-to-seat-everyone
2042-maximum-product-difference-between-two-pairs
2053-kth-distinct-string-in-an-array
2057-smallest-index-with-equal-value
2058-concatenation-of-array
2085-count-common-words-with-one-occurrence
2099-number-of-strings-that-appear-as-substrings-in-word
2125-number-of-laser-beams-in-a-bank
2137-final-value-of-variable-after-performing-operations
2154-keep-multiplying-found-values-by-two
2200-find-all-k-distant-indices-in-an-array
2206-divide-array-into-equal-pairs
2210-find-target-indices-after-sorting-array
2210-count-hills-and-valleys-in-an-array
2219-maximum-number-of-words-found-in-sentences
2231-find-first-palindromic-string-in-the-array
2248-intersection-of-multiple-arrays
2255-count-prefixes-of-a-given-string
2277-count-equal-and-divisible-pairs-in-an-array
2292-counting-words-with-a-given-prefix
2293-min-max-game
2303-calculate-amount-paid-in-taxes
2341-maximum-number-of-pairs-in-array
2357-make-array-zero-by-subtracting-equal-amounts
2363-merge-similar-items
2389-longest-subsequence-with-limited-sum
2441-largest-positive-integer-that-exists-with-its-negative
2442-number-of-arithmetic-triplets
2454-largest-local-values-in-a-matrix
2460-apply-operations-to-an-array
2475-number-of-unequal-triplets-in-array
2496-maximum-value-of-a-string-in-an-array
2500-delete-greatest-value-in-each-row
2502-sort-the-people
2506-count-pairs-of-similar-strings
2529-maximum-count-of-positive-integer-and-negative-integer
2535-difference-between-element-sum-and-digit-sum-of-an-array
2558-take-gifts-from-the-richest-pile
2570-merge-two-2d-arrays-by-summing-values
2586-count-the-number-of-vowel-strings-in-range
2639-separate-the-digits-in-an-array
2643-row-with-maximum-ones
2670-find-the-distinct-difference-array
2678-number-of-senior-citizens
2706-buy-two-chocolates
2714-left-and-right-sum-differences
2717-semi-ordered-permutation
2733-neither-minimum-nor-maximum
2744-find-maximum-number-of-string-pairs
2767-maximum-sum-with-exactly-k-elements
2778-sum-of-squares-of-special-elements
2788-split-strings-by-separator
2824-count-pairs-whose-sum-is-less-than-target
2859-sum-of-values-at-indices-with-k-set-bits
2876-number-of-employees-who-met-the-target
2917-find-the-k-or-of-an-array
2932-maximum-strong-pair-xor-i
2951-find-the-peaks
2956-find-common-elements-between-two-arrays
2960-count-tested-devices-after-test-operations
2977-check-if-a-string-is-an-acronym-of-words
3005-count-elements-with-maximum-frequency
3028-ant-on-the-boundary
3042-count-prefix-and-suffix-pairs-i
3069-distribute-elements-into-two-arrays-i
3074-apple-redistribution-into-boxes
3079-find-the-sum-of-encrypted-integers
3151-special-array-i
3158-find-the-xor-of-numbers-which-appear-twice
3184-count-pairs-that-form-a-complete-day-i
3194-find-words-containing-character
3194-minimum-average-of-smallest-and-largest-elements
3206-alternating-groups-i
3226-minimum-number-game
3227-find-missing-and-repeated-values
3232-find-if-digit-game-can-be-won
3248-snake-in-matrix
3264-final-array-state-after-k-multiplication-operations-i
3300-minimum-element-after-replacement-with-digit-sum
3331-minimum-operations-to-exceed-threshold-value-i
3375-minimum-operations-to-make-array-values-equal-to-k
3397-find-the-integer-added-to-array-i
3423-maximum-difference-between-adjacent-elements-in-a-circular-array
3432-count-partitions-with-even-sum-difference
3446-find-the-number-of-good-pairs-i
3452-sum-of-good-numbers
3476-find-minimum-operations-to-make-all-elements-divisible-by-three
3502-minimum-cost-to-reach-every-position
3512-minimum-operations-to-make-array-sum-divisible-by-k
3550-smallest-index-with-digit-sum-equal-to-index
3581-the-two-sneaky-numbers-of-digitville
3582-find-indices-of-stable-mountains
3663-find-the-least-frequent-digit
3684-maximize-sum-of-at-most-k-distinct-elements
3688-bitwise-or-of-even-numbers-in-an-array
3697-compute-decimal-representation
3712-sum-of-elements-with-frequency-divisible-by-k
3718-smallest-missing-multiple-of-k
3731-sum-of-variable-length-subarrays
3731-find-missing-elements
3736-minimum-moves-to-equal-array-elements-iii
3774-absolute-difference-between-maximum-and-minimum-k-elements
3778-transform-array-by-parity
4012-earliest-time-to-finish-one-task
4058-compute-alternating-sum

Two Pointers

0088-merge-sorted-array
0125-valid-palindrome
0141-linked-list-cycle
0151-reverse-words-in-a-string
0283-move-zeroes
0344-reverse-string
0345-reverse-vowels-of-a-string
0349-intersection-of-two-arrays
0392-is-subsequence
0557-reverse-words-in-a-string-iii
0861-flipping-an-image
0905-sort-array-by-parity
0942-di-string-match
0977-squares-of-a-sorted-array
1455-check-if-a-word-occurs-as-a-prefix-of-any-word-in-a-sentence
1894-merge-strings-alternately
2128-reverse-prefix-of-word
2200-find-all-k-distant-indices-in-an-array
2231-find-first-palindromic-string-in-the-array
2396-strictly-palindromic-number
2441-largest-positive-integer-that-exists-with-its-negative
2442-number-of-arithmetic-triplets
2460-apply-operations-to-an-array
2570-merge-two-2d-arrays-by-summing-values
2697-lexicographically-smallest-palindrome
2824-count-pairs-whose-sum-is-less-than-target
3194-minimum-average-of-smallest-and-largest-elements
3750-minimum-number-of-flips-to-reverse-binary-string
3823-reverse-letters-then-special-characters-in-a-string

Sorting

0088-merge-sorted-array
0169-majority-element
0217-contains-duplicate
0242-valid-anagram
0268-missing-number
0349-intersection-of-two-arrays
0506-relative-ranks
0561-array-partition
0594-longest-harmonious-subsequence
0905-sort-array-by-parity
0977-squares-of-a-sorted-array
1051-height-checker
1122-relative-sort-array
1200-minimum-absolute-difference
1356-sort-integers-by-the-number-of-1-bits
1460-make-two-arrays-equal-by-reversing-subarrays
1482-how-many-numbers-are-smaller-than-the-current-number
1491-average-salary-excluding-the-minimum-and-maximum-salary
1502-can-make-arithmetic-progression-from-sequence
1574-maximum-product-of-two-elements-in-an-array
1636-sort-array-by-increasing-frequency
1637-widest-vertical-area-between-two-points-containing-no-points
1710-maximum-units-on-a-truck
1777-determine-if-two-strings-are-close
1970-sorting-the-sentence
2037-minimum-number-of-moves-to-seat-everyone
2042-maximum-product-difference-between-two-pairs
2154-keep-multiplying-found-values-by-two
2210-find-target-indices-after-sorting-array
2248-intersection-of-multiple-arrays
2264-minimum-sum-of-four-digit-number-after-splitting-digits
2357-make-array-zero-by-subtracting-equal-amounts
2363-merge-similar-items
2389-longest-subsequence-with-limited-sum
2441-largest-positive-integer-that-exists-with-its-negative
2475-number-of-unequal-triplets-in-array
2500-delete-greatest-value-in-each-row
2502-sort-the-people
2706-buy-two-chocolates
2733-neither-minimum-nor-maximum
2824-count-pairs-whose-sum-is-less-than-target
3074-apple-redistribution-into-boxes
3194-minimum-average-of-smallest-and-largest-elements
3226-minimum-number-game
3536-maximum-product-of-two-digits
3545-minimum-deletions-for-at-most-k-distinct-characters
3684-maximize-sum-of-at-most-k-distinct-elements
3731-find-missing-elements
3774-absolute-difference-between-maximum-and-minimum-k-elements
3778-transform-array-by-parity

Tree

0094-binary-tree-inorder-traversal
0100-same-tree
0101-symmetric-tree
0104-maximum-depth-of-binary-tree
0108-convert-sorted-array-to-binary-search-tree
0110-balanced-binary-tree
0111-minimum-depth-of-binary-tree
0112-path-sum
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal

Depth-First Search

0094-binary-tree-inorder-traversal
0100-same-tree
0101-symmetric-tree
0104-maximum-depth-of-binary-tree
0110-balanced-binary-tree
0111-minimum-depth-of-binary-tree
0112-path-sum
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal

Breadth-First Search

0100-same-tree
0101-symmetric-tree
0104-maximum-depth-of-binary-tree
0111-minimum-depth-of-binary-tree
0112-path-sum

Binary Tree

0094-binary-tree-inorder-traversal
0100-same-tree
0101-symmetric-tree
0104-maximum-depth-of-binary-tree
0108-convert-sorted-array-to-binary-search-tree
0110-balanced-binary-tree
0111-minimum-depth-of-binary-tree
0112-path-sum
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal

Divide and Conquer

0108-convert-sorted-array-to-binary-search-tree
0169-majority-element
0190-reverse-bits
0191-number-of-1-bits
1763-longest-nice-substring

Binary Search Tree

0108-convert-sorted-array-to-binary-search-tree

String

0067-add-binary
0125-valid-palindrome
0151-reverse-words-in-a-string
0242-valid-anagram
0344-reverse-string
0345-reverse-vowels-of-a-string
0387-first-unique-character-in-a-string
0392-is-subsequence
0412-fizz-buzz
0500-keyboard-row
0557-reverse-words-in-a-string-iii
0657-robot-return-to-origin
0742-to-lower-case
0782-jewels-and-stones
0796-rotate-string
0804-unique-morse-code-words
0806-number-of-lines-to-write-string
0824-goat-latin
0884-uncommon-words-from-two-sentences
0942-di-string-match
0944-delete-columns-to-make-sorted
1002-find-common-characters
1078-occurrences-after-bigram
1146-greatest-common-divisor-of-strings
1205-defanging-an-ip-address
1221-split-a-string-in-balanced-strings
1309-decrypt-string-from-alphabet-to-integer-mapping
1370-increasing-decreasing-string
1374-generate-a-string-with-characters-that-have-odd-counts
1408-string-matching-in-an-array
1422-maximum-score-after-splitting-a-string
1436-destination-city
1455-check-if-a-word-occurs-as-a-prefix-of-any-word-in-a-sentence
1507-reformat-date
1544-make-the-string-great
1567-maximum-number-of-vowels-in-a-substring-of-given-length
1598-crawler-log-folder
1614-maximum-nesting-depth-of-the-parentheses
1624-largest-substring-between-two-equal-characters
1651-shuffle-string
1694-reformat-phone-number
1704-determine-if-string-halves-are-alike
1758-minimum-changes-to-make-alternating-binary-string
1763-longest-nice-substring
1773-count-items-matching-a-rule
1777-determine-if-two-strings-are-close
1781-check-if-two-string-arrays-are-equivalent
1786-count-the-number-of-consistent-strings
1797-goal-parser-interpretation
1812-determine-color-of-a-chessboard-square
1844-replace-all-digits-with-characters
1876-substrings-of-size-three-with-distinct-characters
1880-check-if-word-equals-summation-of-two-words
1894-merge-strings-alternately
1935-maximum-number-of-words-you-can-type
1941-check-if-all-characters-have-equal-number-of-occurrences
1944-truncate-sentence
1957-delete-characters-to-make-fancy-string
1960-check-if-the-sentence-is-pangram
1970-sorting-the-sentence
2053-kth-distinct-string-in-an-array
2062-count-vowel-substrings-of-a-string
2068-check-whether-two-strings-are-almost-equivalent
2085-count-common-words-with-one-occurrence
2099-number-of-strings-that-appear-as-substrings-in-word
2103-rings-and-rods
2124-check-if-all-as-appears-before-all-bs
2125-number-of-laser-beams-in-a-bank
2128-reverse-prefix-of-word
2129-capitalize-the-title
2137-final-value-of-variable-after-performing-operations
2194-cells-in-a-range-on-an-excel-sheet
2219-maximum-number-of-words-found-in-sentences
2231-find-first-palindromic-string-in-the-array
2255-count-prefixes-of-a-given-string
2264-largest-3-same-digit-number-in-string
2278-percentage-of-letter-in-string
2283-check-if-number-has-equal-digit-count-and-digit-value
2292-counting-words-with-a-given-prefix
2309-greatest-english-letter-in-upper-and-lower-case
2325-decode-the-message
2351-first-letter-to-appear-twice
2401-count-asterisks
2470-removing-stars-from-a-string
2490-circular-sentence
2496-maximum-value-of-a-string-in-an-array
2502-sort-the-people
2506-count-pairs-of-similar-strings
2586-count-the-number-of-vowel-strings-in-range
2678-number-of-senior-citizens
2696-minimum-string-length-after-removing-substrings
2697-lexicographically-smallest-palindrome
2710-remove-trailing-zeros-from-a-string
2716-minimize-string-length
2744-find-maximum-number-of-string-pairs
2788-split-strings-by-separator
2810-faulty-keyboard
2977-check-if-a-string-is-an-acronym-of-words
3019-number-of-changing-keys
3042-count-prefix-and-suffix-pairs-i
3055-maximum-odd-binary-number
3090-maximum-length-substring-with-two-occurrences
3168-minimum-number-of-chairs-in-a-waiting-room
3174-clear-digits
3194-find-words-containing-character
3210-find-the-encrypted-string
3248-snake-in-matrix
3258-count-substrings-that-satisfy-k-constraint-i
3274-check-if-two-chessboard-squares-have-the-same-color
3330-find-the-original-typed-string-i
3379-score-of-a-string
3412-permutation-difference-between-two-strings
3545-minimum-deletions-for-at-most-k-distinct-characters
3567-convert-date-to-binary
3636-check-balanced-string
3692-majority-frequency-characters
3750-minimum-number-of-flips-to-reverse-binary-string
3760-maximum-substrings-with-distinct-start
3768-check-if-digits-are-equal-in-string-after-operations-i
3798-largest-even-number
3811-reverse-degree-of-a-string
3823-reverse-letters-then-special-characters-in-a-string
3872-find-most-frequent-vowel-and-consonant

Bit Manipulation

0067-add-binary
0136-single-number
0190-reverse-bits
0191-number-of-1-bits
0268-missing-number
0338-counting-bits
0461-hamming-distance
0476-number-complement
0693-binary-number-with-alternating-bits
0861-flipping-an-image
1342-number-of-steps-to-reduce-a-number-to-zero
1356-sort-integers-by-the-number-of-1-bits
1486-xor-operation-in-an-array
1720-decode-xored-array
1763-longest-nice-substring
1786-count-the-number-of-consistent-strings
1993-sum-of-all-subset-xor-totals
2032-two-out-of-three
2206-divide-array-into-equal-pairs
2220-minimum-bit-flips-to-convert-number
2351-first-letter-to-appear-twice
2506-count-pairs-of-similar-strings
2595-number-of-even-and-odd-bits
2859-sum-of-values-at-indices-with-k-set-bits
2917-find-the-k-or-of-an-array
2932-maximum-strong-pair-xor-i
3158-find-the-xor-of-numbers-which-appear-twice
3304-find-the-k-th-character-in-string-game-i
3370-smallest-number-with-all-set-bits
3688-bitwise-or-of-even-numbers-in-an-array
3750-minimum-number-of-flips-to-reverse-binary-string

Simulation

0067-add-binary
0258-add-digits
0412-fizz-buzz
0657-robot-return-to-origin
0682-baseball-game
0861-flipping-an-image
1505-create-target-array-in-the-given-order
1708-design-parking-system
1806-count-of-matches-in-tournament
2058-concatenation-of-array
2137-final-value-of-variable-after-performing-operations
2154-keep-multiplying-found-values-by-two
2169-count-operations-to-obtain-zero
2180-count-integers-with-even-digit-sum
2293-min-max-game
2303-calculate-amount-paid-in-taxes
2357-make-array-zero-by-subtracting-equal-amounts
2460-apply-operations-to-an-array
2470-removing-stars-from-a-string
2500-delete-greatest-value-in-each-row
2558-take-gifts-from-the-richest-pile
2639-separate-the-digits-in-an-array
2696-minimum-string-length-after-removing-substrings
2717-semi-ordered-permutation
2744-find-maximum-number-of-string-pairs
2810-faulty-keyboard
2960-count-tested-devices-after-test-operations
3028-ant-on-the-boundary
3069-distribute-elements-into-two-arrays-i
3168-minimum-number-of-chairs-in-a-waiting-room
3174-clear-digits
3226-minimum-number-game
3248-snake-in-matrix
3264-final-array-state-after-k-multiplication-operations-i
3304-find-the-k-th-character-in-string-game-i
3688-bitwise-or-of-even-numbers-in-an-array
3726-remove-zeros-in-decimal-representation
3768-check-if-digits-are-equal-in-string-after-operations-i
3811-reverse-degree-of-a-string
3823-reverse-letters-then-special-characters-in-a-string
4058-compute-alternating-sum

Dynamic Programming

0070-climbing-stairs
0118-pascals-triangle
0119-pascals-triangle-ii
0121-best-time-to-buy-and-sell-stock
0338-counting-bits
0392-is-subsequence
0509-fibonacci-number

Memoization

0070-climbing-stairs
0509-fibonacci-number

Stack

0094-binary-tree-inorder-traversal
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0496-next-greater-element-i
0682-baseball-game
1544-make-the-string-great
1570-final-prices-with-a-special-discount-in-a-shop
1598-crawler-log-folder
1614-maximum-nesting-depth-of-the-parentheses
2128-reverse-prefix-of-word
2470-removing-stars-from-a-string
2696-minimum-string-length-after-removing-substrings
3174-clear-digits

Hash Table

0001-two-sum
0141-linked-list-cycle
0169-majority-element
0217-contains-duplicate
0242-valid-anagram
0268-missing-number
0349-intersection-of-two-arrays
0387-first-unique-character-in-a-string
0448-find-all-numbers-disappeared-in-an-array
0496-next-greater-element-i
0500-keyboard-row
0594-longest-harmonious-subsequence
0782-jewels-and-stones
0804-unique-morse-code-words
0884-uncommon-words-from-two-sentences
1002-find-common-characters
1122-relative-sort-array
1319-unique-number-of-occurrences
1370-increasing-decreasing-string
1392-find-the-difference-of-two-arrays
1394-find-lucky-integer-in-an-array
1399-count-largest-group
1436-destination-city
1460-make-two-arrays-equal-by-reversing-subarrays
1482-how-many-numbers-are-smaller-than-the-current-number
1624-largest-substring-between-two-equal-characters
1635-number-of-good-pairs
1636-sort-array-by-increasing-frequency
1742-maximum-number-of-balls-in-a-box
1748-sum-of-unique-elements
1763-longest-nice-substring
1777-determine-if-two-strings-are-close
1786-count-the-number-of-consistent-strings
1876-substrings-of-size-three-with-distinct-characters
1935-maximum-number-of-words-you-can-type
1941-check-if-all-characters-have-equal-number-of-occurrences
1960-check-if-the-sentence-is-pangram
2006-count-number-of-pairs-with-absolute-difference-k
2032-two-out-of-three
2053-kth-distinct-string-in-an-array
2062-count-vowel-substrings-of-a-string
2068-check-whether-two-strings-are-almost-equivalent
2085-count-common-words-with-one-occurrence
2103-rings-and-rods
2154-keep-multiplying-found-values-by-two
2206-divide-array-into-equal-pairs
2248-intersection-of-multiple-arrays
2283-check-if-number-has-equal-digit-count-and-digit-value
2309-greatest-english-letter-in-upper-and-lower-case
2325-decode-the-message
2341-maximum-number-of-pairs-in-array
2351-first-letter-to-appear-twice
2357-make-array-zero-by-subtracting-equal-amounts
2363-merge-similar-items
2441-largest-positive-integer-that-exists-with-its-negative
2442-number-of-arithmetic-triplets
2475-number-of-unequal-triplets-in-array
2502-sort-the-people
2506-count-pairs-of-similar-strings
2570-merge-two-2d-arrays-by-summing-values
2670-find-the-distinct-difference-array
2716-minimize-string-length
2744-find-maximum-number-of-string-pairs
2932-maximum-strong-pair-xor-i
2956-find-common-elements-between-two-arrays
3005-count-elements-with-maximum-frequency
3090-maximum-length-substring-with-two-occurrences
3158-find-the-xor-of-numbers-which-appear-twice
3184-count-pairs-that-form-a-complete-day-i
3227-find-missing-and-repeated-values
3375-minimum-operations-to-make-array-values-equal-to-k
3412-permutation-difference-between-two-strings
3446-find-the-number-of-good-pairs-i
3545-minimum-deletions-for-at-most-k-distinct-characters
3581-the-two-sneaky-numbers-of-digitville
3663-find-the-least-frequent-digit
3684-maximize-sum-of-at-most-k-distinct-elements
3692-majority-frequency-characters
3712-sum-of-elements-with-frequency-divisible-by-k
3718-smallest-missing-multiple-of-k
3731-find-missing-elements
3760-maximum-substrings-with-distinct-start
3872-find-most-frequent-vowel-and-consonant

Counting

0169-majority-element
0387-first-unique-character-in-a-string
0594-longest-harmonious-subsequence
0884-uncommon-words-from-two-sentences
1221-split-a-string-in-balanced-strings
1356-sort-integers-by-the-number-of-1-bits
1370-increasing-decreasing-string
1394-find-lucky-integer-in-an-array
1635-number-of-good-pairs
1704-determine-if-string-halves-are-alike
1708-design-parking-system
1742-maximum-number-of-balls-in-a-box
1748-sum-of-unique-elements
1777-determine-if-two-strings-are-close
1786-count-the-number-of-consistent-strings
1854-maximum-population-year
1876-substrings-of-size-three-with-distinct-characters
1941-check-if-all-characters-have-equal-number-of-occurrences
2006-count-number-of-pairs-with-absolute-difference-k
2053-kth-distinct-string-in-an-array
2068-check-whether-two-strings-are-almost-equivalent
2085-count-common-words-with-one-occurrence
2206-divide-array-into-equal-pairs
2248-intersection-of-multiple-arrays
2283-check-if-number-has-equal-digit-count-and-digit-value
2341-maximum-number-of-pairs-in-array
2351-first-letter-to-appear-twice
2506-count-pairs-of-similar-strings
2529-maximum-count-of-positive-integer-and-negative-integer
2586-count-the-number-of-vowel-strings-in-range
2960-count-tested-devices-after-test-operations
3005-count-elements-with-maximum-frequency
3184-count-pairs-that-form-a-complete-day-i
3545-minimum-deletions-for-at-most-k-distinct-characters
3663-find-the-least-frequent-digit
3692-majority-frequency-characters
3712-sum-of-elements-with-frequency-divisible-by-k
3778-transform-array-by-parity
3872-find-most-frequent-vowel-and-consonant

Database

0175-combine-two-tables
0176-second-highest-salary
0177-nth-highest-salary
0178-rank-scores
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
0570-managers-with-at-least-5-direct-reports
0577-employee-bonus
0584-find-customer-referee
0585-investments-in-2016
0586-customer-placing-the-largest-number-of-orders
0595-big-countries
0596-classes-more-than-5-students
0602-friend-requests-ii-who-has-the-most-friends
0607-sales-person
0608-tree-node
0610-triangle-judgement
0619-biggest-single-number
0620-not-boring-movies
0626-exchange-seats
0627-swap-salary
1135-customers-who-bought-all-products
1136-actors-and-directors-who-cooperated-at-least-three-times
1153-product-sales-analysis-i
1155-product-sales-analysis-iii
1161-project-employees-i
1174-sales-analysis-iii
1179-game-play-analysis-i
1182-game-play-analysis-iv
1245-user-activity-for-the-past-30-days-i
1258-article-views-i
1268-market-analysis-i
1278-product-price-at-a-given-date
1292-immediate-food-delivery-ii
1301-reformat-department-table
1317-monthly-transactions-i
1327-last-person-to-fit-in-the-bus
1338-queries-quality-and-percentage
1390-average-selling-price
1415-students-and-examinations
1452-restaurant-growth
1462-list-the-products-ordered-in-a-period
1480-movie-rating
1509-replace-employee-id-with-the-unique-identifier
1523-capital-gainloss
1541-top-travellers
1625-group-sold-products-by-the-date
1664-find-users-with-valid-e-mails
1670-patients-with-a-condition
1724-customer-who-visited-but-did-not-make-any-transactions
1734-bank-account-summary-ii
1773-percentage-of-users-attended-a-contest
1801-average-time-of-process-per-machine
1811-fix-names-in-a-table
1827-invalid-tweets
1837-daily-leads-and-partners
1877-find-followers-count
1882-the-number-of-employees-which-report-to-each-employee
1892-find-total-time-spent-by-each-employee
1908-recyclable-and-low-fat-products
1942-primary-department-for-each-employee
1948-rearrange-products-table
2024-calculate-special-bonus
2041-the-latest-login-in-2020
2057-count-salary-categories
2087-confirmation-rate
2110-employees-with-missing-information
2127-employees-whose-manager-left-the-company
2495-number-of-unique-subjects-taught-by-each-teacher
3530-odd-and-even-transactions
3711-first-letter-capitalization-ii
3767-find-students-who-improved
3782-find-valid-emails
3803-find-products-with-valid-serial-numbers
3816-dna-pattern-recognition
3848-analyze-subscription-conversion
3865-find-product-recommendation-pairs
3898-seasonal-sales-analysis
3910-find-books-with-no-available-copies
3921-find-consistently-improving-employees
3932-find-covid-recovery-patients

Matrix

0861-flipping-an-image
1677-matrix-diagonal-sum
1791-richest-customer-wealth
2125-number-of-laser-beams-in-a-bank
2454-largest-local-values-in-a-matrix
2500-delete-greatest-value-in-each-row
2643-row-with-maximum-ones
3227-find-missing-and-repeated-values

Number Theory

0258-add-digits
1952-three-divisors
1979-find-greatest-common-divisor-of-array
2427-number-of-common-factors
2491-smallest-even-multiple
3658-gcd-of-odd-and-even-sums
3768-check-if-digits-are-equal-in-string-after-operations-i

Design

1708-design-parking-system

Greedy

0334-increasing-triplet-subsequence
0561-array-partition
0605-can-place-flowers
0942-di-string-match
1221-split-a-string-in-balanced-strings
1323-maximum-69-number
1710-maximum-units-on-a-truck
1827-minimum-operations-to-make-the-array-increasing
2037-minimum-number-of-moves-to-seat-everyone
2264-minimum-sum-of-four-digit-number-after-splitting-digits
2357-make-array-zero-by-subtracting-equal-amounts
2389-longest-subsequence-with-limited-sum
2697-lexicographically-smallest-palindrome
2706-buy-two-chocolates
2767-maximum-sum-with-exactly-k-elements
3055-maximum-odd-binary-number
3074-apple-redistribution-into-boxes
3545-minimum-deletions-for-at-most-k-distinct-characters
3684-maximize-sum-of-at-most-k-distinct-elements

Prefix Sum

0238-product-of-array-except-self
0724-find-pivot-index
1422-maximum-score-after-splitting-a-string
1603-running-sum-of-1d-array
1693-sum-of-all-odd-length-subarrays
1833-find-the-highest-altitude
1854-maximum-population-year
1991-find-the-middle-index-in-array
2389-longest-subsequence-with-limited-sum
2571-find-the-pivot-integer
2714-left-and-right-sum-differences
3028-ant-on-the-boundary
3432-count-partitions-with-even-sum-difference
3731-sum-of-variable-length-subarrays

Sliding Window

0594-longest-harmonious-subsequence
0643-maximum-average-subarray-i
1567-maximum-number-of-vowels-in-a-substring-of-given-length
1763-longest-nice-substring
1876-substrings-of-size-three-with-distinct-characters
2932-maximum-strong-pair-xor-i
3090-maximum-length-substring-with-two-occurrences
3206-alternating-groups-i
3258-count-substrings-that-satisfy-k-constraint-i

Counting Sort

0561-array-partition
1051-height-checker
1122-relative-sort-array
1482-how-many-numbers-are-smaller-than-the-current-number
2037-minimum-number-of-moves-to-seat-everyone

Enumeration

1534-count-good-triplets
1925-count-square-sum-triples
1952-three-divisors
1993-sum-of-all-subset-xor-totals
2309-greatest-english-letter-in-upper-and-lower-case
2427-number-of-common-factors
2442-number-of-arithmetic-triplets
2778-sum-of-squares-of-special-elements
2843-count-symmetric-integers
2951-find-the-peaks
3345-smallest-divisible-digit-product-i

Heap (Priority Queue)

0506-relative-ranks
1574-maximum-product-of-two-elements-in-an-array
2357-make-array-zero-by-subtracting-equal-amounts
2500-delete-greatest-value-in-each-row
2558-take-gifts-from-the-richest-pile
3226-minimum-number-game
3264-final-array-state-after-k-multiplication-operations-i

String Matching

0796-rotate-string
1408-string-matching-in-an-array
1455-check-if-a-word-occurs-as-a-prefix-of-any-word-in-a-sentence
2292-counting-words-with-a-given-prefix
3042-count-prefix-and-suffix-pairs-i

Backtracking

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

Combinatorics

1993-sum-of-all-subset-xor-totals
3768-check-if-digits-are-equal-in-string-after-operations-i

Geometry

1395-minimum-time-visiting-all-points

Monotonic Stack

0496-next-greater-element-i
1570-final-prices-with-a-special-discount-in-a-shop

Trie

2932-maximum-strong-pair-xor-i
3042-count-prefix-and-suffix-pairs-i

Rolling Hash

3042-count-prefix-and-suffix-pairs-i

Hash Function

3042-count-prefix-and-suffix-pairs-i

Ordered Set

2363-merge-similar-items

Queue

0387-first-unique-character-in-a-string

Brainteaser

2396-strictly-palindromic-number