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

LeetCode Topics

Array

0001-two-sum
0004-median-of-two-sorted-arrays
0033-search-in-rotated-sorted-array
0034-find-first-and-last-position-of-element-in-sorted-array
0041-first-missing-positive
0042-trapping-rain-water
0048-rotate-image
0054-spiral-matrix
0073-set-matrix-zeroes
0074-search-a-2d-matrix
0081-search-in-rotated-sorted-array-ii
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0106-construct-binary-tree-from-inorder-and-postorder-traversal
0108-convert-sorted-array-to-binary-search-tree
0118-pascals-triangle
0137-single-number-ii
0152-maximum-product-subarray
0154-find-minimum-in-rotated-sorted-array-ii
0162-find-peak-element
0204-count-primes
0215-kth-largest-element-in-an-array
0239-sliding-window-maximum
0240-search-a-2d-matrix-ii
0260-single-number-iii
0378-kth-smallest-element-in-a-sorted-matrix
0442-find-all-duplicates-in-an-array
0500-keyboard-row
0713-subarray-product-less-than-k
0717-1-bit-and-2-bit-characters
0777-toeplitz-matrix
0822-unique-morse-code-words
0875-longest-mountain-in-array
0940-fruit-into-baskets
1072-next-greater-node-in-linked-list
1210-mean-of-array-after-removing-some-elements
1319-unique-number-of-occurrences
1426-find-n-unique-integers-sum-up-to-zero
1476-count-negative-numbers-in-a-sorted-matrix
1528-kids-with-the-greatest-number-of-candies
1615-range-sum-of-sorted-subarray-sums
1651-shuffle-string
1755-defuse-the-bomb
1833-find-the-highest-altitude
1848-sum-of-unique-elements
2271-rearrange-array-elements-by-sign
2341-count-prefixes-of-a-given-string
2350-find-closest-number-to-zero
2362-minimum-rounds-to-complete-all-tasks
2411-spiral-matrix-iv
2436-make-array-zero-by-subtracting-equal-amounts
2519-find-the-original-array-of-prefix-xor
2606-difference-between-ones-and-zeros-in-row-and-column
2639-separate-the-digits-in-an-array
2724-convert-an-array-into-a-2d-array-with-conditions
2847-find-maximum-number-of-string-pairs
3094-minimum-number-of-operations-to-make-array-empty
3324-split-the-array
3373-maximum-prime-difference
3397-find-the-integer-added-to-array-i
3421-count-pairs-that-form-a-complete-day-i
3501-delete-nodes-from-linked-list-present-in-array
3515-find-if-digit-game-can-be-won
3541-report-spam-message

Hash Table

0001-two-sum
0003-longest-substring-without-repeating-characters
0013-roman-to-integer
0017-letter-combinations-of-a-phone-number
0041-first-missing-positive
0073-set-matrix-zeroes
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0106-construct-binary-tree-from-inorder-and-postorder-traversal
0142-linked-list-cycle-ii
0160-intersection-of-two-linked-lists
0205-isomorphic-strings
0442-find-all-duplicates-in-an-array
0500-keyboard-row
0822-unique-morse-code-words
0940-fruit-into-baskets
1319-unique-number-of-occurrences
1557-check-if-a-string-contains-all-binary-codes-of-size-k
1848-sum-of-unique-elements
1987-substrings-of-size-three-with-distinct-characters
2362-minimum-rounds-to-complete-all-tasks
2427-first-letter-to-appear-twice
2436-make-array-zero-by-subtracting-equal-amounts
2724-convert-an-array-into-a-2d-array-with-conditions
2847-find-maximum-number-of-string-pairs
3094-minimum-number-of-operations-to-make-array-empty
3324-split-the-array
3412-permutation-difference-between-two-strings
3421-count-pairs-that-form-a-complete-day-i
3501-delete-nodes-from-linked-list-present-in-array
3541-report-spam-message
3871-minimum-deletions-for-at-most-k-distinct-characters

String

0003-longest-substring-without-repeating-characters
0005-longest-palindromic-substring
0008-string-to-integer-atoi
0013-roman-to-integer
0017-letter-combinations-of-a-phone-number
0028-find-the-index-of-the-first-occurrence-in-a-string
0065-valid-number
0151-reverse-words-in-a-string
0205-isomorphic-strings
0412-fizz-buzz
0500-keyboard-row
0504-base-7
0541-reverse-string-ii
0557-reverse-words-in-a-string-iii
0822-unique-morse-code-words
0961-long-pressed-name
1302-delete-characters-to-make-fancy-string
1341-split-a-string-in-balanced-strings
1557-check-if-a-string-contains-all-binary-codes-of-size-k
1651-shuffle-string
1807-partitioning-into-minimum-number-of-deci-binary-numbers
1894-merge-strings-alternately
1970-sorting-the-sentence
1987-substrings-of-size-three-with-distinct-characters
2341-count-prefixes-of-a-given-string
2346-largest-3-same-digit-number-in-string
2427-first-letter-to-appear-twice
2470-removing-stars-from-a-string
2819-remove-trailing-zeros-from-a-string
2847-find-maximum-number-of-string-pairs
3396-valid-word
3412-permutation-difference-between-two-strings
3540-hash-divided-string
3541-report-spam-message
3636-check-balanced-string
3871-minimum-deletions-for-at-most-k-distinct-characters

Sliding Window

0003-longest-substring-without-repeating-characters
0239-sliding-window-maximum
0713-subarray-product-less-than-k
0940-fruit-into-baskets
1755-defuse-the-bomb
1987-substrings-of-size-three-with-distinct-characters

Math

0002-add-two-numbers
0007-reverse-integer
0013-roman-to-integer
0029-divide-two-integers
0048-rotate-image
0204-count-primes
0231-power-of-two
0258-add-digits
0326-power-of-three
0342-power-of-four
0343-integer-break
0412-fizz-buzz
0441-arranging-coins
0445-add-two-numbers-ii
0504-base-7
1013-fibonacci-number
1411-convert-binary-number-in-a-linked-list-to-integer
1426-find-n-unique-integers-sum-up-to-zero
1440-convert-integer-to-the-sum-of-two-no-zero-integers
1444-number-of-steps-to-reduce-a-number-to-zero
1448-maximum-69-number
1585-the-kth-factor-of-n
2481-strictly-palindromic-number
2556-convert-the-temperature
2645-pass-the-pillow
2903-insert-greatest-common-divisors-in-linked-list
3373-maximum-prime-difference
3450-find-the-child-who-has-the-ball-after-k-seconds
3515-find-if-digit-game-can-be-won
3830-find-closest-person
3859-maximum-product-of-two-digits

Matrix

0048-rotate-image
0054-spiral-matrix
0073-set-matrix-zeroes
0074-search-a-2d-matrix
0240-search-a-2d-matrix-ii
0378-kth-smallest-element-in-a-sorted-matrix
0777-toeplitz-matrix
1476-count-negative-numbers-in-a-sorted-matrix
2411-spiral-matrix-iv
2606-difference-between-ones-and-zeros-in-row-and-column

Binary Search

0004-median-of-two-sorted-arrays
0033-search-in-rotated-sorted-array
0034-find-first-and-last-position-of-element-in-sorted-array
0074-search-a-2d-matrix
0081-search-in-rotated-sorted-array-ii
0154-find-minimum-in-rotated-sorted-array-ii
0162-find-peak-element
0222-count-complete-tree-nodes
0240-search-a-2d-matrix-ii
0378-kth-smallest-element-in-a-sorted-matrix
0441-arranging-coins
0713-subarray-product-less-than-k
1476-count-negative-numbers-in-a-sorted-matrix
1615-range-sum-of-sorted-subarray-sums

Stack

0042-trapping-rain-water
0114-flatten-binary-tree-to-linked-list
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0445-add-two-numbers-ii
1072-next-greater-node-in-linked-list
2236-maximum-twin-sum-of-a-linked-list
2470-removing-stars-from-a-string
2573-remove-nodes-from-linked-list

Tree

0100-same-tree
0102-binary-tree-level-order-traversal
0103-binary-tree-zigzag-level-order-traversal
0104-maximum-depth-of-binary-tree
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0106-construct-binary-tree-from-inorder-and-postorder-traversal
0107-binary-tree-level-order-traversal-ii
0108-convert-sorted-array-to-binary-search-tree
0111-minimum-depth-of-binary-tree
0112-path-sum
0114-flatten-binary-tree-to-linked-list
0116-populating-next-right-pointers-in-each-node
0117-populating-next-right-pointers-in-each-node-ii
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0222-count-complete-tree-nodes
0226-invert-binary-tree
0230-kth-smallest-element-in-a-bst
0404-sum-of-left-leaves
0783-search-in-a-binary-search-tree
0784-insert-into-a-binary-search-tree
0975-range-sum-of-bst

Depth-First Search

0100-same-tree
0104-maximum-depth-of-binary-tree
0111-minimum-depth-of-binary-tree
0112-path-sum
0114-flatten-binary-tree-to-linked-list
0116-populating-next-right-pointers-in-each-node
0117-populating-next-right-pointers-in-each-node-ii
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0226-invert-binary-tree
0230-kth-smallest-element-in-a-bst
0404-sum-of-left-leaves
0975-range-sum-of-bst

Binary Tree

0100-same-tree
0102-binary-tree-level-order-traversal
0103-binary-tree-zigzag-level-order-traversal
0104-maximum-depth-of-binary-tree
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0106-construct-binary-tree-from-inorder-and-postorder-traversal
0107-binary-tree-level-order-traversal-ii
0108-convert-sorted-array-to-binary-search-tree
0111-minimum-depth-of-binary-tree
0112-path-sum
0114-flatten-binary-tree-to-linked-list
0116-populating-next-right-pointers-in-each-node
0117-populating-next-right-pointers-in-each-node-ii
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0222-count-complete-tree-nodes
0226-invert-binary-tree
0230-kth-smallest-element-in-a-bst
0404-sum-of-left-leaves
0783-search-in-a-binary-search-tree
0784-insert-into-a-binary-search-tree
0975-range-sum-of-bst

Linked List

0002-add-two-numbers
0019-remove-nth-node-from-end-of-list
0021-merge-two-sorted-lists
0024-swap-nodes-in-pairs
0082-remove-duplicates-from-sorted-list-ii
0092-reverse-linked-list-ii
0114-flatten-binary-tree-to-linked-list
0116-populating-next-right-pointers-in-each-node
0117-populating-next-right-pointers-in-each-node-ii
0142-linked-list-cycle-ii
0147-insertion-sort-list
0148-sort-list
0160-intersection-of-two-linked-lists
0237-delete-node-in-a-linked-list
0328-odd-even-linked-list
0445-add-two-numbers-ii
0528-swapping-nodes-in-a-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
2411-spiral-matrix-iv
2573-remove-nodes-from-linked-list
2903-insert-greatest-common-divisors-in-linked-list
3501-delete-nodes-from-linked-list-present-in-array

Two Pointers

0005-longest-palindromic-substring
0019-remove-nth-node-from-end-of-list
0028-find-the-index-of-the-first-occurrence-in-a-string
0042-trapping-rain-water
0082-remove-duplicates-from-sorted-list-ii
0142-linked-list-cycle-ii
0148-sort-list
0151-reverse-words-in-a-string
0160-intersection-of-two-linked-lists
0528-swapping-nodes-in-a-linked-list
0541-reverse-string-ii
0557-reverse-words-in-a-string-iii
0875-longest-mountain-in-array
0961-long-pressed-name
1615-range-sum-of-sorted-subarray-sums
1894-merge-strings-alternately
2216-delete-the-middle-node-of-a-linked-list
2236-maximum-twin-sum-of-a-linked-list
2271-rearrange-array-elements-by-sign
2481-strictly-palindromic-number

Dynamic Programming

0005-longest-palindromic-substring
0042-trapping-rain-water
0118-pascals-triangle
0152-maximum-product-subarray
0343-integer-break
0875-longest-mountain-in-array
1013-fibonacci-number

Monotonic Stack

0042-trapping-rain-water
1072-next-greater-node-in-linked-list
2573-remove-nodes-from-linked-list

Bit Manipulation

0029-divide-two-integers
0137-single-number-ii
0222-count-complete-tree-nodes
0231-power-of-two
0260-single-number-iii
0342-power-of-four
1444-number-of-steps-to-reduce-a-number-to-zero
1557-check-if-a-string-contains-all-binary-codes-of-size-k
2427-first-letter-to-appear-twice
2519-find-the-original-array-of-prefix-xor

Simulation

0054-spiral-matrix
0258-add-digits
0412-fizz-buzz
2271-rearrange-array-elements-by-sign
2299-merge-nodes-in-between-zeros
2411-spiral-matrix-iv
2436-make-array-zero-by-subtracting-equal-amounts
2470-removing-stars-from-a-string
2606-difference-between-ones-and-zeros-in-row-and-column
2639-separate-the-digits-in-an-array
2645-pass-the-pillow
2847-find-maximum-number-of-string-pairs
3450-find-the-child-who-has-the-ball-after-k-seconds
3540-hash-divided-string

Number Theory

0204-count-primes
0258-add-digits
1585-the-kth-factor-of-n
2903-insert-greatest-common-divisors-in-linked-list
3373-maximum-prime-difference

Database

0182-duplicate-emails
0584-find-customer-referee
0595-big-countries
1258-article-views-i
1827-invalid-tweets
1908-recyclable-and-low-fat-products

Breadth-First Search

0100-same-tree
0102-binary-tree-level-order-traversal
0103-binary-tree-zigzag-level-order-traversal
0104-maximum-depth-of-binary-tree
0107-binary-tree-level-order-traversal-ii
0111-minimum-depth-of-binary-tree
0112-path-sum
0116-populating-next-right-pointers-in-each-node
0117-populating-next-right-pointers-in-each-node-ii
0226-invert-binary-tree
0404-sum-of-left-leaves

Binary Search Tree

0108-convert-sorted-array-to-binary-search-tree
0230-kth-smallest-element-in-a-bst
0783-search-in-a-binary-search-tree
0784-insert-into-a-binary-search-tree
0975-range-sum-of-bst

Sorting

0147-insertion-sort-list
0148-sort-list
0215-kth-largest-element-in-an-array
0378-kth-smallest-element-in-a-sorted-matrix
1210-mean-of-array-after-removing-some-elements
1615-range-sum-of-sorted-subarray-sums
1970-sorting-the-sentence
2436-make-array-zero-by-subtracting-equal-amounts
3859-maximum-product-of-two-digits
3871-minimum-deletions-for-at-most-k-distinct-characters

Counting

1341-split-a-string-in-balanced-strings
1848-sum-of-unique-elements
1987-substrings-of-size-three-with-distinct-characters
2362-minimum-rounds-to-complete-all-tasks
2427-first-letter-to-appear-twice
3094-minimum-number-of-operations-to-make-array-empty
3324-split-the-array
3421-count-pairs-that-form-a-complete-day-i
3871-minimum-deletions-for-at-most-k-distinct-characters

Divide and Conquer

0004-median-of-two-sorted-arrays
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0106-construct-binary-tree-from-inorder-and-postorder-traversal
0108-convert-sorted-array-to-binary-search-tree
0148-sort-list
0215-kth-largest-element-in-an-array
0240-search-a-2d-matrix-ii

Greedy

1341-split-a-string-in-balanced-strings
1448-maximum-69-number
1807-partitioning-into-minimum-number-of-deci-binary-numbers
2362-minimum-rounds-to-complete-all-tasks
2436-make-array-zero-by-subtracting-equal-amounts
3094-minimum-number-of-operations-to-make-array-empty
3871-minimum-deletions-for-at-most-k-distinct-characters

Heap (Priority Queue)

0215-kth-largest-element-in-an-array
0239-sliding-window-maximum
0378-kth-smallest-element-in-a-sorted-matrix
2436-make-array-zero-by-subtracting-equal-amounts

Recursion

0002-add-two-numbers
0021-merge-two-sorted-lists
0024-swap-nodes-in-pairs
0231-power-of-two
0326-power-of-three
0342-power-of-four
1013-fibonacci-number
2573-remove-nodes-from-linked-list

Memoization

1013-fibonacci-number

Merge Sort

0148-sort-list

Queue

0239-sliding-window-maximum

Monotonic Queue

0239-sliding-window-maximum

Prefix Sum

0713-subarray-product-less-than-k
1615-range-sum-of-sorted-subarray-sums
1833-find-the-highest-altitude

Enumeration

0204-count-primes
0875-longest-mountain-in-array

String Matching

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

Backtracking

0017-letter-combinations-of-a-phone-number

Brainteaser

2481-strictly-palindromic-number

Rolling Hash

1557-check-if-a-string-contains-all-binary-codes-of-size-k

Hash Function

1557-check-if-a-string-contains-all-binary-codes-of-size-k

Quickselect

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