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

LeetCode Topics

Array

0015-3sum
0018-4sum
0033-search-in-rotated-sorted-array
0041-first-missing-positive
0056-merge-intervals
0057-insert-interval
0073-set-matrix-zeroes
0074-search-a-2d-matrix
0139-word-break
0153-find-minimum-in-rotated-sorted-array
0300-longest-increasing-subsequence
0410-split-array-largest-sum
0435-non-overlapping-intervals
0560-subarray-sum-equals-k
0605-can-place-flowers
0643-maximum-average-subarray-i
0724-find-pivot-index
0747-min-cost-climbing-stairs
0780-max-chunks-to-make-sorted
0905-length-of-longest-fibonacci-subsequence
0940-fruit-into-baskets
0979-di-string-match
1063-best-sightseeing-pair
1335-maximum-candies-allocated-to-k-children
1364-tuple-with-same-product
1396-count-servers-that-communicate
1468-check-if-n-and-its-double-exist
1510-find-lucky-integer-in-an-array
1524-string-matching-in-an-array
1570-final-prices-with-a-special-discount-in-a-shop
1631-number-of-sub-arrays-with-odd-sum
1679-shortest-subarray-to-be-removed-to-make-array-sorted
1730-special-array-with-x-elements-greater-than-or-equal-x
1878-check-if-array-is-sorted-and-rotated
1895-minimum-number-of-operations-to-move-all-balls-to-each-box
1917-maximum-average-pass-ratio
1927-maximum-ascending-subarray-sum
1951-find-the-winner-of-the-circular-game
1993-sum-of-all-subset-xor-totals
2112-minimum-difference-between-highest-and-lowest-of-k-scores
2170-count-number-of-maximum-bitwise-or-subsets
2265-partition-array-according-to-given-pivot
2308-divide-array-into-equal-pairs
2350-find-closest-number-to-zero
2358-number-of-ways-to-split-array
2478-longest-nice-subarray
2533-bitwise-xor-of-all-pairings
2551-apply-operations-to-an-array
2614-maximum-count-of-positive-integer-and-negative-integer
2640-maximum-number-of-integers-to-choose-from-a-range-i
2665-minimum-time-to-repair-cars
2685-first-completely-painted-row-or-column
2691-count-vowel-strings-in-ranges
2692-take-gifts-from-the-richest-pile
2707-merge-two-2d-arrays-by-summing-values
2716-prime-subtraction-operation
2856-count-complete-subarrays-in-an-array
2868-continuous-subarrays
3143-longest-unequal-adjacent-groups-subsequence-i
3152-maximum-value-of-an-ordered-triplet-ii
3154-maximum-value-of-an-ordered-triplet-i
3194-find-words-containing-character
3227-find-missing-and-repeated-values
3291-find-if-array-can-be-sorted
3309-count-prefix-and-suffix-pairs-i
3321-type-of-triangle
3372-longest-strictly-increasing-or-strictly-decreasing-subarray
3555-final-array-state-after-k-multiplication-operations-i
3621-minimum-operations-to-make-array-values-equal-to-k
3639-zero-array-transformation-i
3656-minimum-number-of-operations-to-make-elements-in-array-distinct
3764-maximum-sum-with-at-most-k-elements
3799-unique-3-digit-even-numbers

Math

0007-reverse-integer
0069-sqrtx
0258-add-digits
0910-nth-magical-number
1146-greatest-common-divisor-of-strings
1236-n-th-tribonacci-number
1631-number-of-sub-arrays-with-odd-sum
1889-check-if-number-is-a-sum-of-powers-of-three
1951-find-the-winner-of-the-circular-game
1993-sum-of-all-subset-xor-totals
2481-strictly-palindromic-number
2649-count-total-number-of-colored-cells
2704-maximum-difference-by-remapping-a-digit
2716-prime-subtraction-operation
2998-count-symmetric-integers
3172-divisible-and-non-divisible-sums-difference
3227-find-missing-and-repeated-values
3321-type-of-triangle
3555-final-array-state-after-k-multiplication-operations-i

Recursion

0021-merge-two-sorted-lists
0203-remove-linked-list-elements
0234-palindrome-linked-list
1667-find-kth-bit-in-nth-binary-string
1951-find-the-winner-of-the-circular-game
3799-unique-3-digit-even-numbers

Queue

1951-find-the-winner-of-the-circular-game
2868-continuous-subarrays

Simulation

0258-add-digits
1667-find-kth-bit-in-nth-binary-string
1951-find-the-winner-of-the-circular-game
2265-partition-array-according-to-given-pivot
2551-apply-operations-to-an-array
2692-take-gifts-from-the-richest-pile
3555-final-array-state-after-k-multiplication-operations-i

Backtracking

0022-generate-parentheses
1160-letter-tile-possibilities
1715-split-a-string-into-the-max-number-of-unique-substrings
1993-sum-of-all-subset-xor-totals
2170-count-number-of-maximum-bitwise-or-subsets
2456-construct-smallest-number-from-di-string

Bit Manipulation

1873-longest-nice-substring
1993-sum-of-all-subset-xor-totals
2170-count-number-of-maximum-bitwise-or-subsets
2308-divide-array-into-equal-pairs
2478-longest-nice-subarray
2533-bitwise-xor-of-all-pairings
3291-find-if-array-can-be-sorted

Enumeration

1993-sum-of-all-subset-xor-totals
2170-count-number-of-maximum-bitwise-or-subsets
2998-count-symmetric-integers
3799-unique-3-digit-even-numbers

String

0003-longest-substring-without-repeating-characters
0022-generate-parentheses
0028-find-the-index-of-the-first-occurrence-in-a-string
0139-word-break
0151-reverse-words-in-a-string
0214-shortest-palindrome
0392-is-subsequence
0979-di-string-match
1146-greatest-common-divisor-of-strings
1160-letter-tile-possibilities
1460-number-of-substrings-containing-all-three-characters
1502-construct-k-palindrome-strings
1524-string-matching-in-an-array
1537-maximum-score-after-splitting-a-string
1566-check-if-a-word-occurs-as-a-prefix-of-any-word-in-a-sentence
1667-find-kth-bit-in-nth-binary-string
1715-split-a-string-into-the-max-number-of-unique-substrings
1873-longest-nice-substring
1894-merge-strings-alternately
1895-minimum-number-of-operations-to-move-all-balls-to-each-box
1915-check-if-one-string-swap-can-make-strings-equal
1987-substrings-of-size-three-with-distinct-characters
2186-count-vowel-substrings-of-a-string
2373-apply-discount-to-prices
2456-construct-smallest-number-from-di-string
2691-count-vowel-strings-in-ranges
3018-make-string-a-subsequence-using-cyclic-increments
3143-longest-unequal-adjacent-groups-subsequence-i
3194-find-words-containing-character
3309-count-prefix-and-suffix-pairs-i
3451-string-compression-iii
3502-count-substrings-with-k-frequency-characters-i
3753-maximum-difference-between-even-and-odd-frequency-i

Dynamic Programming

0022-generate-parentheses
0139-word-break
0300-longest-increasing-subsequence
0392-is-subsequence
0410-split-array-largest-sum
0435-non-overlapping-intervals
0747-min-cost-climbing-stairs
0905-length-of-longest-fibonacci-subsequence
1063-best-sightseeing-pair
1236-n-th-tribonacci-number
1631-number-of-sub-arrays-with-odd-sum
2562-count-ways-to-build-good-strings
3143-longest-unequal-adjacent-groups-subsequence-i

Hash Table

0003-longest-substring-without-repeating-characters
0041-first-missing-positive
0073-set-matrix-zeroes
0139-word-break
0141-linked-list-cycle
0160-intersection-of-two-linked-lists
0560-subarray-sum-equals-k
0905-length-of-longest-fibonacci-subsequence
0940-fruit-into-baskets
1160-letter-tile-possibilities
1364-tuple-with-same-product
1460-number-of-substrings-containing-all-three-characters
1468-check-if-n-and-its-double-exist
1502-construct-k-palindrome-strings
1510-find-lucky-integer-in-an-array
1715-split-a-string-into-the-max-number-of-unique-substrings
1873-longest-nice-substring
1915-check-if-one-string-swap-can-make-strings-equal
1987-substrings-of-size-three-with-distinct-characters
2186-count-vowel-substrings-of-a-string
2308-divide-array-into-equal-pairs
2640-maximum-number-of-integers-to-choose-from-a-range-i
2685-first-completely-painted-row-or-column
2707-merge-two-2d-arrays-by-summing-values
2856-count-complete-subarrays-in-an-array
3227-find-missing-and-repeated-values
3502-count-substrings-with-k-frequency-characters-i
3621-minimum-operations-to-make-array-values-equal-to-k
3656-minimum-number-of-operations-to-make-elements-in-array-distinct
3753-maximum-difference-between-even-and-odd-frequency-i
3799-unique-3-digit-even-numbers

Tree

0515-find-largest-value-in-each-tree-row
1035-cousins-in-binary-tree
2493-reverse-odd-levels-of-binary-tree
2558-minimum-number-of-operations-to-sort-a-binary-tree-by-level
2646-kth-largest-sum-in-a-binary-tree

Breadth-First Search

0515-find-largest-value-in-each-tree-row
1035-cousins-in-binary-tree
1396-count-servers-that-communicate
2493-reverse-odd-levels-of-binary-tree
2558-minimum-number-of-operations-to-sort-a-binary-tree-by-level
2646-kth-largest-sum-in-a-binary-tree

Sorting

0015-3sum
0018-4sum
0056-merge-intervals
0435-non-overlapping-intervals
0780-max-chunks-to-make-sorted
1468-check-if-n-and-its-double-exist
1730-special-array-with-x-elements-greater-than-or-equal-x
2112-minimum-difference-between-highest-and-lowest-of-k-scores
2640-maximum-number-of-integers-to-choose-from-a-range-i
2646-kth-largest-sum-in-a-binary-tree
3291-find-if-array-can-be-sorted
3321-type-of-triangle
3764-maximum-sum-with-at-most-k-elements

Binary Tree

0515-find-largest-value-in-each-tree-row
1035-cousins-in-binary-tree
2493-reverse-odd-levels-of-binary-tree
2558-minimum-number-of-operations-to-sort-a-binary-tree-by-level
2646-kth-largest-sum-in-a-binary-tree

Depth-First Search

0515-find-largest-value-in-each-tree-row
1035-cousins-in-binary-tree
1396-count-servers-that-communicate
2493-reverse-odd-levels-of-binary-tree

Database

0197-rising-temperature

Sliding Window

0003-longest-substring-without-repeating-characters
0643-maximum-average-subarray-i
0940-fruit-into-baskets
1460-number-of-substrings-containing-all-three-characters
1873-longest-nice-substring
1987-substrings-of-size-three-with-distinct-characters
2112-minimum-difference-between-highest-and-lowest-of-k-scores
2478-longest-nice-subarray
2856-count-complete-subarrays-in-an-array
2868-continuous-subarrays
3502-count-substrings-with-k-frequency-characters-i

Divide and Conquer

1873-longest-nice-substring

Greedy

0410-split-array-largest-sum
0435-non-overlapping-intervals
0605-can-place-flowers
0780-max-chunks-to-make-sorted
0979-di-string-match
1502-construct-k-palindrome-strings
1917-maximum-average-pass-ratio
2456-construct-smallest-number-from-di-string
2640-maximum-number-of-integers-to-choose-from-a-range-i
2704-maximum-difference-by-remapping-a-digit
2716-prime-subtraction-operation
3143-longest-unequal-adjacent-groups-subsequence-i
3764-maximum-sum-with-at-most-k-elements

Binary Search

0033-search-in-rotated-sorted-array
0069-sqrtx
0074-search-a-2d-matrix
0153-find-minimum-in-rotated-sorted-array
0300-longest-increasing-subsequence
0374-guess-number-higher-or-lower
0410-split-array-largest-sum
0910-nth-magical-number
1335-maximum-candies-allocated-to-k-children
1468-check-if-n-and-its-double-exist
1679-shortest-subarray-to-be-removed-to-make-array-sorted
1730-special-array-with-x-elements-greater-than-or-equal-x
2614-maximum-count-of-positive-integer-and-negative-integer
2640-maximum-number-of-integers-to-choose-from-a-range-i
2665-minimum-time-to-repair-cars
2716-prime-subtraction-operation

Number Theory

0258-add-digits
2716-prime-subtraction-operation

Two Pointers

0015-3sum
0018-4sum
0028-find-the-index-of-the-first-occurrence-in-a-string
0141-linked-list-cycle
0151-reverse-words-in-a-string
0160-intersection-of-two-linked-lists
0234-palindrome-linked-list
0392-is-subsequence
0979-di-string-match
1468-check-if-n-and-its-double-exist
1566-check-if-a-word-occurs-as-a-prefix-of-any-word-in-a-sentence
1679-shortest-subarray-to-be-removed-to-make-array-sorted
1894-merge-strings-alternately
2265-partition-array-according-to-given-pivot
2481-strictly-palindromic-number
2551-apply-operations-to-an-array
2707-merge-two-2d-arrays-by-summing-values
3018-make-string-a-subsequence-using-cyclic-increments

Stack

0234-palindrome-linked-list
0780-max-chunks-to-make-sorted
1570-final-prices-with-a-special-discount-in-a-shop
1679-shortest-subarray-to-be-removed-to-make-array-sorted
2456-construct-smallest-number-from-di-string

Monotonic Stack

0780-max-chunks-to-make-sorted
1570-final-prices-with-a-special-discount-in-a-shop
1679-shortest-subarray-to-be-removed-to-make-array-sorted

String Matching

0028-find-the-index-of-the-first-occurrence-in-a-string
0214-shortest-palindrome
1524-string-matching-in-an-array
1566-check-if-a-word-occurs-as-a-prefix-of-any-word-in-a-sentence
3309-count-prefix-and-suffix-pairs-i

Heap (Priority Queue)

1917-maximum-average-pass-ratio
2692-take-gifts-from-the-richest-pile
2868-continuous-subarrays
3555-final-array-state-after-k-multiplication-operations-i
3764-maximum-sum-with-at-most-k-elements

Ordered Set

2868-continuous-subarrays

Monotonic Queue

2868-continuous-subarrays

Prefix Sum

0410-split-array-largest-sum
0560-subarray-sum-equals-k
0724-find-pivot-index
1537-maximum-score-after-splitting-a-string
1631-number-of-sub-arrays-with-odd-sum
1895-minimum-number-of-operations-to-move-all-balls-to-each-box
2358-number-of-ways-to-split-array
2691-count-vowel-strings-in-ranges
3639-zero-array-transformation-i

Trie

0139-word-break
3309-count-prefix-and-suffix-pairs-i

Rolling Hash

0214-shortest-palindrome
3309-count-prefix-and-suffix-pairs-i

Hash Function

0214-shortest-palindrome
3309-count-prefix-and-suffix-pairs-i

Counting

1160-letter-tile-possibilities
1364-tuple-with-same-product
1396-count-servers-that-communicate
1502-construct-k-palindrome-strings
1510-find-lucky-integer-in-an-array
1915-check-if-one-string-swap-can-make-strings-equal
1987-substrings-of-size-three-with-distinct-characters
2308-divide-array-into-equal-pairs
2614-maximum-count-of-positive-integer-and-negative-integer
3753-maximum-difference-between-even-and-odd-frequency-i

Brainteaser

2481-strictly-palindromic-number
2533-bitwise-xor-of-all-pairings

Linked List

0021-merge-two-sorted-lists
0141-linked-list-cycle
0160-intersection-of-two-linked-lists
0203-remove-linked-list-elements
0234-palindrome-linked-list

Matrix

0073-set-matrix-zeroes
0074-search-a-2d-matrix
1396-count-servers-that-communicate
2685-first-completely-painted-row-or-column
3227-find-missing-and-repeated-values
3764-maximum-sum-with-at-most-k-elements

Union Find

1396-count-servers-that-communicate

Interactive

0374-guess-number-higher-or-lower

Memoization

0139-word-break
1236-n-th-tribonacci-number

Combinatorics

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