LeetHub

A collection of LeetCode questions to ace the coding interview!

Math

0007-reverse-integer
0009-palindrome-number
0189-rotate-array
0268-missing-number
0507-perfect-number
0728-self-dividing-numbers
1013-fibonacci-number
1406-subtract-the-product-and-sum-of-digits-of-an-integer

Two Pointers

0026-remove-duplicates-from-sorted-array
0031-next-permutation
0075-sort-colors
0125-valid-palindrome
0189-rotate-array
0283-move-zeroes
0349-intersection-of-two-arrays
2271-rearrange-array-elements-by-sign

String

0125-valid-palindrome

Dynamic Programming

0121-best-time-to-buy-and-sell-stock
1013-fibonacci-number

Recursion

0206-reverse-linked-list
1013-fibonacci-number

Memoization

1013-fibonacci-number

Array

0001-two-sum
0026-remove-duplicates-from-sorted-array
0031-next-permutation
0073-set-matrix-zeroes
0075-sort-colors
0121-best-time-to-buy-and-sell-stock
0128-longest-consecutive-sequence
0136-single-number
0169-majority-element
0189-rotate-array
0200-number-of-islands
0268-missing-number
0283-move-zeroes
0349-intersection-of-two-arrays
0442-find-all-duplicates-in-an-array
0485-max-consecutive-ones
0560-subarray-sum-equals-k
0733-flood-fill
0882-peak-index-in-a-mountain-array
1231-replace-elements-with-greatest-element-on-right-side
1319-unique-number-of-occurrences
2271-rearrange-array-elements-by-sign

Hash Table

0001-two-sum
0073-set-matrix-zeroes
0128-longest-consecutive-sequence
0169-majority-element
0268-missing-number
0349-intersection-of-two-arrays
0442-find-all-duplicates-in-an-array
0560-subarray-sum-equals-k
1319-unique-number-of-occurrences

Binary Search

0268-missing-number
0349-intersection-of-two-arrays
0882-peak-index-in-a-mountain-array

Bit Manipulation

0136-single-number
0191-number-of-1-bits
0268-missing-number
0476-number-complement
1054-complement-of-base-10-integer

Sorting

0075-sort-colors
0169-majority-element
0268-missing-number
0349-intersection-of-two-arrays

Divide and Conquer

0169-majority-element
0191-number-of-1-bits

Counting

0169-majority-element

Simulation

2271-rearrange-array-elements-by-sign

Prefix Sum

0560-subarray-sum-equals-k

Union Find

0128-longest-consecutive-sequence
0200-number-of-islands

Matrix

0073-set-matrix-zeroes
0200-number-of-islands
0733-flood-fill

Linked List

0206-reverse-linked-list

Tree

0450-delete-node-in-a-bst

Binary Search Tree

0450-delete-node-in-a-bst

Binary Tree

0450-delete-node-in-a-bst

Depth-First Search

0200-number-of-islands
0733-flood-fill

Breadth-First Search

0200-number-of-islands
0733-flood-fill

LeetCode Topics

Depth-First Search

0386-lexicographical-numbers
0744-network-delay-time
0988-flip-equivalent-binary-trees
1350-remove-sub-folders-from-the-filesystem
1484-linked-list-in-binary-tree
2201-valid-arrangement-of-pairs
2545-height-of-binary-tree-after-subtree-removal-queries
2677-cousins-in-binary-tree-ii

Breadth-First Search

0744-network-delay-time
0787-sliding-puzzle
1484-linked-list-in-binary-tree
2375-minimum-obstacle-removal-to-reach-corner
2545-height-of-binary-tree-after-subtree-removal-queries
2646-kth-largest-sum-in-a-binary-tree
2677-cousins-in-binary-tree-ii
2711-minimum-time-to-visit-a-cell-in-a-grid
3517-shortest-distance-after-road-addition-queries-i

Graph

0744-network-delay-time
2201-valid-arrangement-of-pairs
2375-minimum-obstacle-removal-to-reach-corner
2711-minimum-time-to-visit-a-cell-in-a-grid
3517-shortest-distance-after-road-addition-queries-i

Heap (Priority Queue)

0632-smallest-range-covering-elements-from-k-lists
0744-network-delay-time
0892-shortest-subarray-with-sum-at-least-k
1304-longest-happy-string
2054-the-number-of-the-smallest-unoccupied-chair
2375-minimum-obstacle-removal-to-reach-corner
2488-divide-intervals-into-minimum-number-of-groups
2616-maximal-score-after-applying-k-operations
2711-minimum-time-to-visit-a-cell-in-a-grid

Shortest Path

0744-network-delay-time
2375-minimum-obstacle-removal-to-reach-corner
2711-minimum-time-to-visit-a-cell-in-a-grid

Linked List

0002-add-two-numbers
0141-linked-list-cycle
0237-delete-node-in-a-linked-list
0432-all-oone-data-structure
0725-split-linked-list-in-parts
0859-design-circular-deque
1484-linked-list-in-binary-tree
2411-spiral-matrix-iv
2903-insert-greatest-common-divisors-in-linked-list
3501-delete-nodes-from-linked-list-present-in-array

Hash Table

0141-linked-list-cycle
0432-all-oone-data-structure
0567-permutation-in-string
0632-smallest-range-covering-elements-from-k-lists
0906-walking-robot-simulation
0920-uncommon-words-from-two-sentences
1147-flip-columns-for-maximum-number-of-equal-rows
1256-rank-transform-of-an-array
1473-find-the-longest-substring-containing-vowels-in-even-counts
1620-check-if-array-pairs-are-divisible-by-k
1694-make-sum-divisible-by-p
1715-split-a-string-into-the-max-number-of-unique-substrings
1786-count-the-number-of-consistent-strings
2054-the-number-of-the-smallest-unoccupied-chair
2356-largest-combination-with-bitwise-and-greater-than-zero
2552-maximum-sum-of-distinct-subarrays-with-length-k
2586-longest-square-streak-in-an-array
2599-take-k-of-each-character-from-left-and-right
2677-cousins-in-binary-tree-ii
2755-extra-characters-in-a-string
3329-find-the-length-of-the-longest-common-prefix
3501-delete-nodes-from-linked-list-present-in-array

Two Pointers

0141-linked-list-cycle
0567-permutation-in-string
1679-shortest-subarray-to-be-removed-to-make-array-sorted
1923-sentence-similarity-iii
1972-rotating-the-box
2095-minimum-number-of-swaps-to-make-the-string-balanced
2488-divide-intervals-into-minimum-number-of-groups
2699-count-the-number-of-fair-pairs
3195-separate-black-and-white-balls

Array

0034-find-first-and-last-position-of-element-in-sorted-array
0035-search-insert-position
0179-largest-number
0539-minimum-time-difference
0632-smallest-range-covering-elements-from-k-lists
0729-my-calendar-i
0731-my-calendar-ii
0787-sliding-puzzle
0792-binary-search
0859-design-circular-deque
0892-shortest-subarray-with-sum-at-least-k
0906-walking-robot-simulation
1002-maximum-width-ramp
1147-flip-columns-for-maximum-number-of-equal-rows
1256-rank-transform-of-an-array
1350-remove-sub-folders-from-the-filesystem
1402-count-square-submatrices-with-all-ones
1435-xor-queries-of-a-subarray
1497-design-a-stack-with-increment-operation
1620-check-if-array-pairs-are-divisible-by-k
1679-shortest-subarray-to-be-removed-to-make-array-sorted
1694-make-sum-divisible-by-p
1755-defuse-the-bomb
1766-minimum-number-of-removals-to-make-mountain-array
1786-count-the-number-of-consistent-strings
1923-sentence-similarity-iii
1940-maximum-xor-for-each-query
1972-rotating-the-box
2006-find-the-student-that-will-replace-the-chalk
2054-the-number-of-the-smallest-unoccupied-chair
2089-maximum-matrix-sum
2132-convert-1d-array-into-2d-array
2155-find-missing-observations
2170-count-number-of-maximum-bitwise-or-subsets
2179-most-beautiful-item-for-each-query
2188-minimized-maximum-of-products-distributed-to-any-store
2343-count-unguarded-cells-in-the-grid
2356-largest-combination-with-bitwise-and-greater-than-zero
2375-minimum-obstacle-removal-to-reach-corner
2411-spiral-matrix-iv
2488-divide-intervals-into-minimum-number-of-groups
2494-sum-of-prefix-scores-of-strings
2503-longest-subarray-with-maximum-bitwise-and
2545-height-of-binary-tree-after-subtree-removal-queries
2552-maximum-sum-of-distinct-subarrays-with-length-k
2554-minimum-total-distance-traveled
2586-longest-square-streak-in-an-array
2616-maximal-score-after-applying-k-operations
2699-count-the-number-of-fair-pairs
2711-minimum-time-to-visit-a-cell-in-a-grid
2716-prime-subtraction-operation
2755-extra-characters-in-a-string
3329-find-the-length-of-the-longest-common-prefix
3380-shortest-subarray-with-or-at-least-k-ii
3501-delete-nodes-from-linked-list-present-in-array
3517-shortest-distance-after-road-addition-queries-i
3522-find-the-power-of-k-size-subarrays-i

Binary Search

0034-find-first-and-last-position-of-element-in-sorted-array
0035-search-insert-position
0729-my-calendar-i
0731-my-calendar-ii
0792-binary-search
0892-shortest-subarray-with-sum-at-least-k
1679-shortest-subarray-to-be-removed-to-make-array-sorted
1766-minimum-number-of-removals-to-make-mountain-array
2006-find-the-student-that-will-replace-the-chalk
2179-most-beautiful-item-for-each-query
2188-minimized-maximum-of-products-distributed-to-any-store
2586-longest-square-streak-in-an-array
2699-count-the-number-of-fair-pairs
2716-prime-subtraction-operation

Matrix

0787-sliding-puzzle
1147-flip-columns-for-maximum-number-of-equal-rows
1402-count-square-submatrices-with-all-ones
1972-rotating-the-box
2089-maximum-matrix-sum
2132-convert-1d-array-into-2d-array
2343-count-unguarded-cells-in-the-grid
2375-minimum-obstacle-removal-to-reach-corner
2411-spiral-matrix-iv
2711-minimum-time-to-visit-a-cell-in-a-grid

Simulation

0906-walking-robot-simulation
1667-find-kth-bit-in-nth-binary-string
2006-find-the-student-that-will-replace-the-chalk
2076-sum-of-digits-of-string-after-convert
2132-convert-1d-array-into-2d-array
2155-find-missing-observations
2343-count-unguarded-cells-in-the-grid
2411-spiral-matrix-iv
2800-minimum-string-length-after-removing-substrings

Prefix Sum

0731-my-calendar-ii
0892-shortest-subarray-with-sum-at-least-k
1435-xor-queries-of-a-subarray
1473-find-the-longest-substring-containing-vowels-in-even-counts
1694-make-sum-divisible-by-p
1940-maximum-xor-for-each-query
2006-find-the-student-that-will-replace-the-chalk
2488-divide-intervals-into-minimum-number-of-groups

String

0179-largest-number
0214-shortest-palindrome
0241-different-ways-to-add-parentheses
0539-minimum-time-difference
0567-permutation-in-string
0920-uncommon-words-from-two-sentences
0957-minimum-add-to-make-parentheses-valid
1197-parsing-a-boolean-expression
1302-delete-characters-to-make-fancy-string
1304-longest-happy-string
1350-remove-sub-folders-from-the-filesystem
1473-find-the-longest-substring-containing-vowels-in-even-counts
1667-find-kth-bit-in-nth-binary-string
1715-split-a-string-into-the-max-number-of-unique-substrings
1786-count-the-number-of-consistent-strings
1923-sentence-similarity-iii
2076-sum-of-digits-of-string-after-convert
2095-minimum-number-of-swaps-to-make-the-string-balanced
2494-sum-of-prefix-scores-of-strings
2580-circular-sentence
2599-take-k-of-each-character-from-left-and-right
2755-extra-characters-in-a-string
2800-minimum-string-length-after-removing-substrings
3174-minimum-number-of-changes-to-make-binary-string-beautiful
3195-separate-black-and-white-balls
3329-find-the-length-of-the-longest-common-prefix
3451-string-compression-iii

Math

0002-add-two-numbers
0241-different-ways-to-add-parentheses
0539-minimum-time-difference
0670-maximum-swap
2155-find-missing-observations
2716-prime-subtraction-operation
2903-insert-greatest-common-divisors-in-linked-list

Tree

0988-flip-equivalent-binary-trees
1484-linked-list-in-binary-tree
2545-height-of-binary-tree-after-subtree-removal-queries
2646-kth-largest-sum-in-a-binary-tree
2677-cousins-in-binary-tree-ii

Binary Tree

0988-flip-equivalent-binary-trees
1484-linked-list-in-binary-tree
2545-height-of-binary-tree-after-subtree-removal-queries
2646-kth-largest-sum-in-a-binary-tree
2677-cousins-in-binary-tree-ii

Recursion

0002-add-two-numbers
0241-different-ways-to-add-parentheses
1197-parsing-a-boolean-expression
1667-find-kth-bit-in-nth-binary-string

Number Theory

2716-prime-subtraction-operation
2903-insert-greatest-common-divisors-in-linked-list

Bit Manipulation

1435-xor-queries-of-a-subarray
1473-find-the-longest-substring-containing-vowels-in-even-counts
1786-count-the-number-of-consistent-strings
1940-maximum-xor-for-each-query
2170-count-number-of-maximum-bitwise-or-subsets
2323-minimum-bit-flips-to-convert-number
2356-largest-combination-with-bitwise-and-greater-than-zero
2503-longest-subarray-with-maximum-bitwise-and
3380-shortest-subarray-with-or-at-least-k-ii
3394-minimum-array-end

Counting

0920-uncommon-words-from-two-sentences
1620-check-if-array-pairs-are-divisible-by-k
1786-count-the-number-of-consistent-strings
2356-largest-combination-with-bitwise-and-greater-than-zero
2494-sum-of-prefix-scores-of-strings

Brainteaser

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

Sorting

0179-largest-number
0539-minimum-time-difference
0632-smallest-range-covering-elements-from-k-lists
1256-rank-transform-of-an-array
2179-most-beautiful-item-for-each-query
2488-divide-intervals-into-minimum-number-of-groups
2554-minimum-total-distance-traveled
2586-longest-square-streak-in-an-array
2646-kth-largest-sum-in-a-binary-tree
2699-count-the-number-of-fair-pairs

Greedy

0179-largest-number
0632-smallest-range-covering-elements-from-k-lists
0670-maximum-swap
0957-minimum-add-to-make-parentheses-valid
1304-longest-happy-string
1766-minimum-number-of-removals-to-make-mountain-array
2089-maximum-matrix-sum
2095-minimum-number-of-swaps-to-make-the-string-balanced
2488-divide-intervals-into-minimum-number-of-groups
2616-maximal-score-after-applying-k-operations
2716-prime-subtraction-operation
3195-separate-black-and-white-balls

Dynamic Programming

0241-different-ways-to-add-parentheses
1402-count-square-submatrices-with-all-ones
1766-minimum-number-of-removals-to-make-mountain-array
2554-minimum-total-distance-traveled
2586-longest-square-streak-in-an-array
2755-extra-characters-in-a-string

Memoization

0241-different-ways-to-add-parentheses

Rolling Hash

0214-shortest-palindrome

String Matching

0214-shortest-palindrome

Hash Function

0214-shortest-palindrome

Trie

0386-lexicographical-numbers
0440-k-th-smallest-in-lexicographical-order
1350-remove-sub-folders-from-the-filesystem
2494-sum-of-prefix-scores-of-strings
2755-extra-characters-in-a-string
3329-find-the-length-of-the-longest-common-prefix

Design

0432-all-oone-data-structure
0729-my-calendar-i
0731-my-calendar-ii
0859-design-circular-deque
1497-design-a-stack-with-increment-operation

Segment Tree

0729-my-calendar-i
0731-my-calendar-ii

Ordered Set

0729-my-calendar-i
0731-my-calendar-ii

Queue

0859-design-circular-deque
0892-shortest-subarray-with-sum-at-least-k

Doubly-Linked List

0432-all-oone-data-structure

Stack

0957-minimum-add-to-make-parentheses-valid
1002-maximum-width-ramp
1197-parsing-a-boolean-expression
1497-design-a-stack-with-increment-operation
1679-shortest-subarray-to-be-removed-to-make-array-sorted
2095-minimum-number-of-swaps-to-make-the-string-balanced
2800-minimum-string-length-after-removing-substrings

Sliding Window

0567-permutation-in-string
0632-smallest-range-covering-elements-from-k-lists
0892-shortest-subarray-with-sum-at-least-k
1755-defuse-the-bomb
2552-maximum-sum-of-distinct-subarrays-with-length-k
2599-take-k-of-each-character-from-left-and-right
3380-shortest-subarray-with-or-at-least-k-ii
3522-find-the-power-of-k-size-subarrays-i

Monotonic Stack

1002-maximum-width-ramp
1679-shortest-subarray-to-be-removed-to-make-array-sorted

Backtracking

1715-split-a-string-into-the-max-number-of-unique-substrings
2170-count-number-of-maximum-bitwise-or-subsets

Enumeration

2170-count-number-of-maximum-bitwise-or-subsets

Monotonic Queue

0892-shortest-subarray-with-sum-at-least-k

Eulerian Circuit

2201-valid-arrangement-of-pairs