Leetcode

LeetCode Topics

Array

0001-two-sum
0011-container-with-most-water
0026-remove-duplicates-from-sorted-array
0027-remove-element
0033-search-in-rotated-sorted-array
0039-combination-sum
0048-rotate-image
0049-group-anagrams
0053-maximum-subarray
0054-spiral-matrix
0064-minimum-path-sum
0073-set-matrix-zeroes
0080-remove-duplicates-from-sorted-array-ii
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0106-construct-binary-tree-from-inorder-and-postorder-traversal
0118-pascals-triangle
0121-best-time-to-buy-and-sell-stock
0136-single-number
0150-evaluate-reverse-polish-notation
0152-maximum-product-subarray
0153-find-minimum-in-rotated-sorted-array
0162-find-peak-element
0167-two-sum-ii-input-array-is-sorted
0179-largest-number
0189-rotate-array
0204-count-primes
0217-contains-duplicate
0238-product-of-array-except-self
0240-search-a-2d-matrix-ii
0283-move-zeroes
0287-find-the-duplicate-number
0349-intersection-of-two-arrays
0378-kth-smallest-element-in-a-sorted-matrix
0435-non-overlapping-intervals
0452-minimum-number-of-arrows-to-burst-balloons
0455-assign-cookies
0485-max-consecutive-ones
0498-diagonal-traverse
0540-single-element-in-a-sorted-array
0605-can-place-flowers
0643-maximum-average-subarray-i
0665-non-decreasing-array
0682-baseball-game
0695-max-area-of-island
0724-find-pivot-index
0733-flood-fill
0739-daily-temperatures
0748-largest-number-at-least-twice-of-others
0792-binary-search
0817-design-hashmap
0860-design-circular-queue
0861-flipping-an-image
0898-transpose-matrix
0905-length-of-longest-fibonacci-subsequence
0917-boats-to-save-people
0948-sort-an-array
0958-sort-array-by-parity-ii
0982-minimum-increment-to-make-array-unique
1020-longest-turbulent-subarray
1031-add-to-array-form-of-integer
1039-find-the-town-judge
1072-next-greater-node-in-linked-list
1127-last-stone-weight
1137-height-checker
1168-duplicate-zeros
1217-relative-sort-array
1256-rank-transform-of-an-array
1306-minimum-absolute-difference
1319-unique-number-of-occurrences
1349-check-if-it-is-a-straight-line
1402-count-square-submatrices-with-all-ones
1421-find-numbers-with-even-number-of-digits
1426-find-n-unique-integers-sum-up-to-zero
1510-find-lucky-integer-in-an-array
1603-running-sum-of-1d-array
1631-number-of-sub-arrays-with-odd-sum
1651-shuffle-string
1656-count-good-triplets
1755-defuse-the-bomb
1781-check-if-two-string-arrays-are-equivalent
1786-count-the-number-of-consistent-strings
1791-richest-customer-wealth
1813-maximum-erasure-value
1849-maximum-absolute-sum-of-any-subarray
1895-minimum-number-of-operations-to-move-all-balls-to-each-box
1951-find-the-winner-of-the-circular-game
1984-maximum-distance-between-a-pair-of-values
2042-maximum-product-difference-between-two-pairs
2102-find-the-middle-index-in-array
2106-find-greatest-common-divisor-of-array
2107-find-unique-binary-string
2137-final-value-of-variable-after-performing-operations
2144-maximum-difference-between-increasing-elements
2199-two-furthest-houses-with-different-colors
2210-find-target-indices-after-sorting-array
2219-maximum-number-of-words-found-in-sentences
2248-minimum-cost-of-buying-candies-with-discount
2265-partition-array-according-to-given-pivot
2271-rearrange-array-elements-by-sign
2274-keep-multiplying-found-values-by-two
2316-count-hills-and-valleys-in-an-array
2329-maximum-product-after-k-increments
2442-number-of-arithmetic-triplets
2497-maximum-matching-of-players-with-trainers
2502-sort-the-people
2551-apply-operations-to-an-array
2564-most-profitable-path-in-a-tree
2566-number-of-unequal-triplets-in-array
2614-maximum-count-of-positive-integer-and-negative-integer
2631-sort-the-students-by-their-kth-score
2639-separate-the-digits-in-an-array
2707-merge-two-2d-arrays-by-summing-values
2714-left-and-right-sum-differences
2836-neither-minimum-nor-maximum
2876-number-of-employees-who-met-the-target
2881-split-strings-by-separator
2917-count-pairs-whose-sum-is-less-than-target
3152-maximum-value-of-an-ordered-triplet-ii
3154-maximum-value-of-an-ordered-triplet-i
3176-minimum-sum-of-mountain-triplets-i
3220-count-tested-devices-after-test-operations
3221-find-the-peaks
3226-minimum-number-game
3227-find-missing-and-repeated-values
3321-type-of-triangle
3331-minimum-operations-to-exceed-threshold-value-i
3334-apple-redistribution-into-boxes
3397-find-the-integer-added-to-array-i
3446-find-the-number-of-good-pairs-i
3471-minimum-average-of-smallest-and-largest-elements
3476-find-minimum-operations-to-make-all-elements-divisible-by-three
3501-delete-nodes-from-linked-list-present-in-array
3656-minimum-number-of-operations-to-make-elements-in-array-distinct
3778-transform-array-by-parity
3846-minimum-operations-to-make-array-sum-divisible-by-k

Hash Table

0001-two-sum
0003-longest-substring-without-repeating-characters
0049-group-anagrams
0073-set-matrix-zeroes
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0106-construct-binary-tree-from-inorder-and-postorder-traversal
0141-linked-list-cycle
0142-linked-list-cycle-ii
0146-lru-cache
0160-intersection-of-two-linked-lists
0202-happy-number
0205-isomorphic-strings
0217-contains-duplicate
0242-valid-anagram
0349-intersection-of-two-arrays
0387-first-unique-character-in-a-string
0438-find-all-anagrams-in-a-string
0451-sort-characters-by-frequency
0567-permutation-in-string
0782-jewels-and-stones
0817-design-hashmap
0905-length-of-longest-fibonacci-subsequence
1039-find-the-town-judge
1217-relative-sort-array
1256-rank-transform-of-an-array
1319-unique-number-of-occurrences
1387-find-elements-in-a-contaminated-binary-tree
1460-number-of-substrings-containing-all-three-characters
1510-find-lucky-integer-in-an-array
1786-count-the-number-of-consistent-strings
1813-maximum-erasure-value
1960-check-if-the-sentence-is-pangram
1987-substrings-of-size-three-with-distinct-characters
2107-find-unique-binary-string
2274-keep-multiplying-found-values-by-two
2427-first-letter-to-appear-twice
2442-number-of-arithmetic-triplets
2502-sort-the-people
2566-number-of-unequal-triplets-in-array
2707-merge-two-2d-arrays-by-summing-values
2824-check-if-the-number-is-fascinating
3227-find-missing-and-repeated-values
3408-count-the-number-of-special-characters-i
3446-find-the-number-of-good-pairs-i
3501-delete-nodes-from-linked-list-present-in-array
3656-minimum-number-of-operations-to-make-elements-in-array-distinct
3753-maximum-difference-between-even-and-odd-frequency-i
3872-find-most-frequent-vowel-and-consonant

String

0003-longest-substring-without-repeating-characters
0008-string-to-integer-atoi
0014-longest-common-prefix
0020-valid-parentheses
0028-find-the-index-of-the-first-occurrence-in-a-string
0049-group-anagrams
0067-add-binary
0072-edit-distance
0179-largest-number
0205-isomorphic-strings
0227-basic-calculator-ii
0242-valid-anagram
0344-reverse-string
0387-first-unique-character-in-a-string
0392-is-subsequence
0394-decode-string
0412-fizz-buzz
0415-add-strings
0438-find-all-anagrams-in-a-string
0451-sort-characters-by-frequency
0567-permutation-in-string
0680-valid-palindrome-ii
0742-to-lower-case
0782-jewels-and-stones
0957-minimum-add-to-make-parentheses-valid
1078-remove-outermost-parentheses
1093-recover-a-tree-from-preorder-traversal
1128-remove-all-adjacent-duplicates-in-string
1170-shortest-common-supersequence
1205-defanging-an-ip-address
1302-delete-characters-to-make-fancy-string
1430-find-the-k-beauty-of-a-number
1460-number-of-substrings-containing-all-three-characters
1542-consecutive-characters
1561-rearrange-words-in-a-sentence
1651-shuffle-string
1666-make-the-string-great
1781-check-if-two-string-arrays-are-equivalent
1786-count-the-number-of-consistent-strings
1797-goal-parser-interpretation
1823-determine-if-string-halves-are-alike
1894-merge-strings-alternately
1895-minimum-number-of-operations-to-move-all-balls-to-each-box
1954-replace-all-digits-with-characters
1960-check-if-the-sentence-is-pangram
1970-sorting-the-sentence
1987-substrings-of-size-three-with-distinct-characters
2107-find-unique-binary-string
2128-reverse-prefix-of-word
2137-final-value-of-variable-after-performing-operations
2168-check-if-numbers-are-ascending-in-a-sentence
2219-maximum-number-of-words-found-in-sentences
2346-largest-3-same-digit-number-in-string
2401-count-asterisks
2427-first-letter-to-appear-twice
2456-construct-smallest-number-from-di-string
2502-sort-the-people
2881-split-strings-by-separator
2887-sort-vowels-in-a-string
3396-valid-word
3408-count-the-number-of-special-characters-i
3617-find-the-original-typed-string-i
3753-maximum-difference-between-even-and-odd-frequency-i
3811-reverse-degree-of-a-string
3872-find-most-frequent-vowel-and-consonant

Two Pointers

0011-container-with-most-water
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
0061-rotate-list
0080-remove-duplicates-from-sorted-array-ii
0141-linked-list-cycle
0142-linked-list-cycle-ii
0143-reorder-list
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
0349-intersection-of-two-arrays
0392-is-subsequence
0455-assign-cookies
0528-swapping-nodes-in-a-linked-list
0567-permutation-in-string
0680-valid-palindrome-ii
0861-flipping-an-image
0908-middle-of-the-linked-list
0917-boats-to-save-people
0958-sort-array-by-parity-ii
1168-duplicate-zeros
1894-merge-strings-alternately
1984-maximum-distance-between-a-pair-of-values
2128-reverse-prefix-of-word
2216-delete-the-middle-node-of-a-linked-list
2236-maximum-twin-sum-of-a-linked-list
2265-partition-array-according-to-given-pivot
2271-rearrange-array-elements-by-sign
2442-number-of-arithmetic-triplets
2481-strictly-palindromic-number
2497-maximum-matching-of-players-with-trainers
2551-apply-operations-to-an-array
2707-merge-two-2d-arrays-by-summing-values
2917-count-pairs-whose-sum-is-less-than-target
3471-minimum-average-of-smallest-and-largest-elements

Simulation

0054-spiral-matrix
0067-add-binary
0258-add-digits
0412-fizz-buzz
0415-add-strings
0498-diagonal-traverse
0682-baseball-game
0861-flipping-an-image
0898-transpose-matrix
1195-distribute-candies-to-people
1806-count-of-matches-in-tournament
1951-find-the-winner-of-the-circular-game
2137-final-value-of-variable-after-performing-operations
2265-partition-array-according-to-given-pivot
2271-rearrange-array-elements-by-sign
2274-keep-multiplying-found-values-by-two
2288-count-operations-to-obtain-zero
2299-merge-nodes-in-between-zeros
2551-apply-operations-to-an-array
2639-separate-the-digits-in-an-array
2857-total-distance-traveled
3220-count-tested-devices-after-test-operations
3226-minimum-number-game
3811-reverse-degree-of-a-string

Sorting

0049-group-anagrams
0179-largest-number
0217-contains-duplicate
0242-valid-anagram
0349-intersection-of-two-arrays
0378-kth-smallest-element-in-a-sorted-matrix
0435-non-overlapping-intervals
0451-sort-characters-by-frequency
0452-minimum-number-of-arrows-to-burst-balloons
0455-assign-cookies
0748-largest-number-at-least-twice-of-others
0917-boats-to-save-people
0948-sort-an-array
0958-sort-array-by-parity-ii
0982-minimum-increment-to-make-array-unique
1137-height-checker
1217-relative-sort-array
1256-rank-transform-of-an-array
1306-minimum-absolute-difference
1561-rearrange-words-in-a-sentence
1970-sorting-the-sentence
2042-maximum-product-difference-between-two-pairs
2210-find-target-indices-after-sorting-array
2248-minimum-cost-of-buying-candies-with-discount
2274-keep-multiplying-found-values-by-two
2497-maximum-matching-of-players-with-trainers
2502-sort-the-people
2566-number-of-unequal-triplets-in-array
2631-sort-the-students-by-their-kth-score
2836-neither-minimum-nor-maximum
2887-sort-vowels-in-a-string
2917-count-pairs-whose-sum-is-less-than-target
3226-minimum-number-game
3321-type-of-triangle
3334-apple-redistribution-into-boxes
3471-minimum-average-of-smallest-and-largest-elements
3778-transform-array-by-parity

Backtracking

0039-combination-sum
0077-combinations
2107-find-unique-binary-string
2456-construct-smallest-number-from-di-string

Binary Search

0033-search-in-rotated-sorted-array
0069-sqrtx
0153-find-minimum-in-rotated-sorted-array
0162-find-peak-element
0167-two-sum-ii-input-array-is-sorted
0240-search-a-2d-matrix-ii
0287-find-the-duplicate-number
0349-intersection-of-two-arrays
0367-valid-perfect-square
0378-kth-smallest-element-in-a-sorted-matrix
0441-arranging-coins
0540-single-element-in-a-sorted-array
0792-binary-search
1984-maximum-distance-between-a-pair-of-values
2210-find-target-indices-after-sorting-array
2614-maximum-count-of-positive-integer-and-negative-integer
2917-count-pairs-whose-sum-is-less-than-target

Math

0002-add-two-numbers
0009-palindrome-number
0048-rotate-image
0062-unique-paths
0067-add-binary
0069-sqrtx
0070-climbing-stairs
0150-evaluate-reverse-polish-notation
0189-rotate-array
0202-happy-number
0204-count-primes
0227-basic-calculator-ii
0231-power-of-two
0258-add-digits
0319-bulb-switcher
0326-power-of-three
0342-power-of-four
0367-valid-perfect-square
0412-fizz-buzz
0415-add-strings
0441-arranging-coins
0445-add-two-numbers-ii
0504-base-7
0507-perfect-number
0728-self-dividing-numbers
0767-prime-number-of-set-bits-in-binary-representation
1031-add-to-array-form-of-integer
1195-distribute-candies-to-people
1236-n-th-tribonacci-number
1289-day-of-the-week
1303-minimum-moves-to-reach-target-score
1349-check-if-it-is-a-straight-line
1406-subtract-the-product-and-sum-of-digits-of-an-integer
1411-convert-binary-number-in-a-linked-list-to-integer
1421-find-numbers-with-even-number-of-digits
1426-find-n-unique-integers-sum-up-to-zero
1430-find-the-k-beauty-of-a-number
1444-number-of-steps-to-reduce-a-number-to-zero
1448-maximum-69-number
1630-count-odd-numbers-in-an-interval-range
1631-number-of-sub-arrays-with-odd-sum
1806-count-of-matches-in-tournament
1817-calculate-money-in-leetcode-bank
1889-check-if-number-is-a-sum-of-powers-of-three
1951-find-the-winner-of-the-circular-game
2083-three-divisors
2106-find-greatest-common-divisor-of-array
2238-a-number-after-a-double-reversal
2288-count-operations-to-obtain-zero
2481-strictly-palindromic-number
2507-number-of-common-factors
2610-closest-prime-numbers-in-range
2630-alternating-digit-sum
2649-count-total-number-of-colored-cells
2715-k-items-with-the-maximum-sum
2752-sum-multiples
2812-find-the-maximum-achievable-number
2824-check-if-the-number-is-fascinating
2857-total-distance-traveled
2871-double-a-number-represented-as-a-linked-list
2903-insert-greatest-common-divisors-in-linked-list
3227-find-missing-and-repeated-values
3321-type-of-triangle
3371-harshad-number
3476-find-minimum-operations-to-make-all-elements-divisible-by-three
3830-find-closest-person
3846-minimum-operations-to-make-array-sum-divisible-by-k

Dynamic Programming

0053-maximum-subarray
0062-unique-paths
0064-minimum-path-sum
0070-climbing-stairs
0072-edit-distance
0118-pascals-triangle
0121-best-time-to-buy-and-sell-stock
0152-maximum-product-subarray
0392-is-subsequence
0435-non-overlapping-intervals
0905-length-of-longest-fibonacci-subsequence
1020-longest-turbulent-subarray
1170-shortest-common-supersequence
1236-n-th-tribonacci-number
1402-count-square-submatrices-with-all-ones
1631-number-of-sub-arrays-with-odd-sum
1849-maximum-absolute-sum-of-any-subarray

Memoization

0070-climbing-stairs
1236-n-th-tribonacci-number

Tree

0094-binary-tree-inorder-traversal
0098-validate-binary-search-tree
0100-same-tree
0104-maximum-depth-of-binary-tree
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0106-construct-binary-tree-from-inorder-and-postorder-traversal
0110-balanced-binary-tree
0112-path-sum
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0226-invert-binary-tree
0230-kth-smallest-element-in-a-bst
0236-lowest-common-ancestor-of-a-binary-tree
0450-delete-node-in-a-bst
0501-find-mode-in-binary-search-tree
0543-diameter-of-binary-tree
0764-n-ary-tree-level-order-traversal
0774-maximum-depth-of-n-ary-tree
0775-n-ary-tree-preorder-traversal
0783-search-in-a-binary-search-tree
0784-insert-into-a-binary-search-tree
0789-kth-largest-element-in-a-stream
1093-recover-a-tree-from-preorder-traversal
1387-find-elements-in-a-contaminated-binary-tree
2384-root-equals-sum-of-children
2564-most-profitable-path-in-a-tree

Depth-First Search

0094-binary-tree-inorder-traversal
0098-validate-binary-search-tree
0100-same-tree
0104-maximum-depth-of-binary-tree
0110-balanced-binary-tree
0112-path-sum
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0226-invert-binary-tree
0230-kth-smallest-element-in-a-bst
0236-lowest-common-ancestor-of-a-binary-tree
0501-find-mode-in-binary-search-tree
0543-diameter-of-binary-tree
0695-max-area-of-island
0733-flood-fill
0774-maximum-depth-of-n-ary-tree
0775-n-ary-tree-preorder-traversal
1093-recover-a-tree-from-preorder-traversal
1387-find-elements-in-a-contaminated-binary-tree
2121-find-if-path-exists-in-graph
2564-most-profitable-path-in-a-tree

Breadth-First Search

0100-same-tree
0104-maximum-depth-of-binary-tree
0112-path-sum
0226-invert-binary-tree
0695-max-area-of-island
0733-flood-fill
0764-n-ary-tree-level-order-traversal
0774-maximum-depth-of-n-ary-tree
1387-find-elements-in-a-contaminated-binary-tree
2121-find-if-path-exists-in-graph
2564-most-profitable-path-in-a-tree

Design

0146-lru-cache
0155-min-stack
0225-implement-stack-using-queues
0232-implement-queue-using-stacks
0789-kth-largest-element-in-a-stream
0817-design-hashmap
0838-design-linked-list
0860-design-circular-queue
1387-find-elements-in-a-contaminated-binary-tree

Binary Tree

0094-binary-tree-inorder-traversal
0098-validate-binary-search-tree
0100-same-tree
0104-maximum-depth-of-binary-tree
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0106-construct-binary-tree-from-inorder-and-postorder-traversal
0110-balanced-binary-tree
0112-path-sum
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0226-invert-binary-tree
0230-kth-smallest-element-in-a-bst
0236-lowest-common-ancestor-of-a-binary-tree
0450-delete-node-in-a-bst
0501-find-mode-in-binary-search-tree
0543-diameter-of-binary-tree
0783-search-in-a-binary-search-tree
0784-insert-into-a-binary-search-tree
0789-kth-largest-element-in-a-stream
1093-recover-a-tree-from-preorder-traversal
1387-find-elements-in-a-contaminated-binary-tree
2384-root-equals-sum-of-children

Sliding Window

0003-longest-substring-without-repeating-characters
0438-find-all-anagrams-in-a-string
0567-permutation-in-string
0643-maximum-average-subarray-i
1020-longest-turbulent-subarray
1430-find-the-k-beauty-of-a-number
1460-number-of-substrings-containing-all-three-characters
1755-defuse-the-bomb
1813-maximum-erasure-value
1987-substrings-of-size-three-with-distinct-characters

Stack

0020-valid-parentheses
0094-binary-tree-inorder-traversal
0143-reorder-list
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0150-evaluate-reverse-polish-notation
0155-min-stack
0225-implement-stack-using-queues
0227-basic-calculator-ii
0232-implement-queue-using-stacks
0234-palindrome-linked-list
0394-decode-string
0445-add-two-numbers-ii
0682-baseball-game
0739-daily-temperatures
0775-n-ary-tree-preorder-traversal
0957-minimum-add-to-make-parentheses-valid
1072-next-greater-node-in-linked-list
1078-remove-outermost-parentheses
1128-remove-all-adjacent-duplicates-in-string
1666-make-the-string-great
2128-reverse-prefix-of-word
2236-maximum-twin-sum-of-a-linked-list
2456-construct-smallest-number-from-di-string
2871-double-a-number-represented-as-a-linked-list

Greedy

0011-container-with-most-water
0179-largest-number
0435-non-overlapping-intervals
0452-minimum-number-of-arrows-to-burst-balloons
0455-assign-cookies
0605-can-place-flowers
0680-valid-palindrome-ii
0917-boats-to-save-people
0957-minimum-add-to-make-parentheses-valid
0982-minimum-increment-to-make-array-unique
1303-minimum-moves-to-reach-target-score
1448-maximum-69-number
2199-two-furthest-houses-with-different-colors
2248-minimum-cost-of-buying-candies-with-discount
2329-maximum-product-after-k-increments
2456-construct-smallest-number-from-di-string
2497-maximum-matching-of-players-with-trainers
2715-k-items-with-the-maximum-sum
3334-apple-redistribution-into-boxes

Graph

1039-find-the-town-judge
2121-find-if-path-exists-in-graph
2564-most-profitable-path-in-a-tree

Heap (Priority Queue)

0378-kth-smallest-element-in-a-sorted-matrix
0451-sort-characters-by-frequency
0789-kth-largest-element-in-a-stream
0948-sort-an-array
1127-last-stone-weight
2329-maximum-product-after-k-increments
3226-minimum-number-game

Matrix

0048-rotate-image
0054-spiral-matrix
0064-minimum-path-sum
0073-set-matrix-zeroes
0240-search-a-2d-matrix-ii
0378-kth-smallest-element-in-a-sorted-matrix
0498-diagonal-traverse
0695-max-area-of-island
0733-flood-fill
0861-flipping-an-image
0898-transpose-matrix
1402-count-square-submatrices-with-all-ones
1791-richest-customer-wealth
2631-sort-the-students-by-their-kth-score
3227-find-missing-and-repeated-values

Prefix Sum

0238-product-of-array-except-self
0724-find-pivot-index
1603-running-sum-of-1d-array
1631-number-of-sub-arrays-with-odd-sum
1895-minimum-number-of-operations-to-move-all-balls-to-each-box
2102-find-the-middle-index-in-array
2714-left-and-right-sum-differences

Divide and Conquer

0053-maximum-subarray
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0106-construct-binary-tree-from-inorder-and-postorder-traversal
0190-reverse-bits
0191-number-of-1-bits
0240-search-a-2d-matrix-ii
0948-sort-an-array

Trie

0014-longest-common-prefix

Number Theory

0204-count-primes
0258-add-digits
2083-three-divisors
2106-find-greatest-common-divisor-of-array
2507-number-of-common-factors
2610-closest-prime-numbers-in-range
2903-insert-greatest-common-divisors-in-linked-list

Recursion

0002-add-two-numbers
0021-merge-two-sorted-lists
0024-swap-nodes-in-pairs
0143-reorder-list
0203-remove-linked-list-elements
0206-reverse-linked-list
0231-power-of-two
0234-palindrome-linked-list
0326-power-of-three
0342-power-of-four
0394-decode-string
1951-find-the-winner-of-the-circular-game

Counting

0387-first-unique-character-in-a-string
0451-sort-characters-by-frequency
0982-minimum-increment-to-make-array-unique
1510-find-lucky-integer-in-an-array
1786-count-the-number-of-consistent-strings
1823-determine-if-string-halves-are-alike
1987-substrings-of-size-three-with-distinct-characters
2427-first-letter-to-appear-twice
2614-maximum-count-of-positive-integer-and-negative-integer
3220-count-tested-devices-after-test-operations
3753-maximum-difference-between-even-and-odd-frequency-i
3778-transform-array-by-parity
3872-find-most-frequent-vowel-and-consonant

Database

0183-customers-who-never-order
0620-not-boring-movies
1258-article-views-i
1664-find-users-with-valid-e-mails

Bucket Sort

0451-sort-characters-by-frequency
0948-sort-an-array

Enumeration

0204-count-primes
1656-count-good-triplets
2083-three-divisors
2442-number-of-arithmetic-triplets
2507-number-of-common-factors
3221-find-the-peaks

Counting Sort

0948-sort-an-array
1137-height-checker
1217-relative-sort-array

Brainteaser

0319-bulb-switcher
2481-strictly-palindromic-number

Bit Manipulation

0067-add-binary
0136-single-number
0190-reverse-bits
0191-number-of-1-bits
0231-power-of-two
0287-find-the-duplicate-number
0342-power-of-four
0461-hamming-distance
0767-prime-number-of-set-bits-in-binary-representation
0861-flipping-an-image
1444-number-of-steps-to-reduce-a-number-to-zero
1786-count-the-number-of-consistent-strings
2323-minimum-bit-flips-to-convert-number
2427-first-letter-to-appear-twice

String Matching

0028-find-the-index-of-the-first-occurrence-in-a-string

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

Linked List

0002-add-two-numbers
0019-remove-nth-node-from-end-of-list
0021-merge-two-sorted-lists
0024-swap-nodes-in-pairs
0061-rotate-list
0083-remove-duplicates-from-sorted-list
0141-linked-list-cycle
0142-linked-list-cycle-ii
0143-reorder-list
0146-lru-cache
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
0528-swapping-nodes-in-a-linked-list
0817-design-hashmap
0838-design-linked-list
0860-design-circular-queue
0908-middle-of-the-linked-list
1072-next-greater-node-in-linked-list
1411-convert-binary-number-in-a-linked-list-to-integer
1765-merge-in-between-linked-lists
2216-delete-the-middle-node-of-a-linked-list
2236-maximum-twin-sum-of-a-linked-list
2299-merge-nodes-in-between-zeros
2871-double-a-number-represented-as-a-linked-list
2903-insert-greatest-common-divisors-in-linked-list
3501-delete-nodes-from-linked-list-present-in-array

Doubly-Linked List

0146-lru-cache

Binary Search Tree

0098-validate-binary-search-tree
0230-kth-smallest-element-in-a-bst
0450-delete-node-in-a-bst
0501-find-mode-in-binary-search-tree
0783-search-in-a-binary-search-tree
0784-insert-into-a-binary-search-tree
0789-kth-largest-element-in-a-stream

Data Stream

0789-kth-largest-element-in-a-stream

Merge Sort

0948-sort-an-array

Radix Sort

0948-sort-an-array

Monotonic Stack

0739-daily-temperatures
1072-next-greater-node-in-linked-list

Hash Function

0817-design-hashmap

Union Find

0695-max-area-of-island
2121-find-if-path-exists-in-graph

Combinatorics

0062-unique-paths

Geometry

1349-check-if-it-is-a-straight-line