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

LeetCode Topics

Array

Problem Name	Difficulty
0001-two-sum
0014-longest-common-prefix
0026-remove-duplicates-from-sorted-array
0027-remove-element
0034-find-first-and-last-position-of-element-in-sorted-array
0035-search-insert-position
0051-n-queens	Hard
0053-maximum-subarray	Medium
0055-jump-game	Medium
0056-merge-intervals
0066-plus-one
0078-subsets	Medium
0118-pascals-triangle
0153-find-minimum-in-rotated-sorted-array
0167-two-sum-ii-input-array-is-sorted
0169-majority-element
0179-largest-number	Medium
0217-contains-duplicate
0219-contains-duplicate-ii
0229-majority-element-ii
0238-product-of-array-except-self
0268-missing-number
0283-move-zeroes
0304-range-sum-query-2d-immutable	Medium
0330-patching-array
0448-find-all-numbers-disappeared-in-an-array
0455-assign-cookies
0485-max-consecutive-ones
0486-predict-the-winner	Medium
0496-next-greater-element-i
0560-subarray-sum-equals-k	Medium
0641-design-circular-deque	Medium
0643-maximum-average-subarray-i
0645-set-mismatch
0661-image-smoother	Easy
0682-baseball-game
0690-employee-importance	Medium
0739-daily-temperatures
0781-rabbits-in-forest	Medium
0792-binary-search
0811-subdomain-visit-count	Medium
0860-lemonade-change	Easy
0907-koko-eating-bananas
0917-boats-to-save-people
0974-subarray-sums-divisible-by-k	Medium
0976-largest-perimeter-triangle	Easy
1011-capacity-to-ship-packages-within-d-days
1029-two-city-scheduling	Medium
1056-capacity-to-ship-packages-within-d-days
1365-how-many-numbers-are-smaller-than-the-current-number
1413-minimum-value-to-get-positive-step-by-step-sum	Easy
1441-build-an-array-with-stack-operations	Medium
1470-shuffle-the-array
1472-design-browser-history	Medium
1480-running-sum-of-1d-array
1590-make-sum-divisible-by-p
1598-crawler-log-folder	Easy
1646-kth-missing-positive-number
1752-arithmetic-subarrays
1798-max-number-of-k-sum-pairs
1929-concatenation-of-array
2058-concatenation-of-array
2102-find-the-middle-index-in-array
2137-final-value-of-variable-after-performing-operations
2305-fair-distribution-of-cookies	Medium
2316-count-hills-and-valleys-in-an-array
2324-find-triangular-sum-of-an-array
2465-shifting-letters-ii
2540-minimum-common-value
2581-divide-players-into-teams-of-equal-skill
2639-separate-the-digits-in-an-array
2824-count-pairs-whose-sum-is-less-than-target
3043-find-the-length-of-the-longest-common-prefix
3191-minimum-operations-to-make-binary-array-elements-equal-to-one-i	Medium
3512-minimum-operations-to-make-array-sum-divisible-by-k

Two Pointers

Problem Name	Difficulty
0026-remove-duplicates-from-sorted-array
0027-remove-element
0125-valid-palindrome
0167-two-sum-ii-input-array-is-sorted
0234-palindrome-linked-list
0283-move-zeroes
0455-assign-cookies
0567-permutation-in-string
0653-two-sum-iv-input-is-a-bst	Easy
0844-backspace-string-compare
0917-boats-to-save-people
0925-long-pressed-name
1798-max-number-of-k-sum-pairs
2000-reverse-prefix-of-word
2540-minimum-common-value
2581-divide-players-into-teams-of-equal-skill
2824-count-pairs-whose-sum-is-less-than-target

Math

Problem Name	Difficulty
0013-roman-to-integer
0066-plus-one
0067-add-binary
0171-excel-sheet-column-number
0224-basic-calculator
0268-missing-number
0342-power-of-four	Easy
0412-fizz-buzz
0415-add-strings
0486-predict-the-winner	Medium
0509-fibonacci-number	Easy
0781-rabbits-in-forest	Medium
0976-largest-perimeter-triangle	Easy
1922-count-good-numbers	Medium
2324-find-triangular-sum-of-an-array
2413-smallest-even-multiple
2556-convert-the-temperature
3512-minimum-operations-to-make-array-sum-divisible-by-k

Simulation

Problem Name	Difficulty
0067-add-binary
0412-fizz-buzz
0415-add-strings
0682-baseball-game
0844-backspace-string-compare
1441-build-an-array-with-stack-operations	Medium
1929-concatenation-of-array
2058-concatenation-of-array
2137-final-value-of-variable-after-performing-operations
2324-find-triangular-sum-of-an-array
2390-removing-stars-from-a-string	Medium
2639-separate-the-digits-in-an-array
3174-clear-digits

String

Problem Name	Difficulty
0013-roman-to-integer
0014-longest-common-prefix
0020-valid-parentheses
0067-add-binary
0071-simplify-path	Medium
0076-minimum-window-substring
0125-valid-palindrome
0171-excel-sheet-column-number
0179-largest-number	Medium
0224-basic-calculator
0383-ransom-note
0387-first-unique-character-in-a-string
0412-fizz-buzz
0415-add-strings
0438-find-all-anagrams-in-a-string
0451-sort-characters-by-frequency
0567-permutation-in-string
0811-subdomain-visit-count	Medium
0844-backspace-string-compare
0856-score-of-parentheses	Medium
0925-long-pressed-name
1598-crawler-log-folder	Easy
1987-substrings-of-size-three-with-distinct-characters
2000-reverse-prefix-of-word
2137-final-value-of-variable-after-performing-operations
2390-removing-stars-from-a-string	Medium
2465-shifting-letters-ii
3043-find-the-length-of-the-longest-common-prefix
3174-clear-digits

Hash Table

Problem Name	Difficulty
0001-two-sum
0013-roman-to-integer
0076-minimum-window-substring
0169-majority-element
0217-contains-duplicate
0219-contains-duplicate-ii
0229-majority-element-ii
0268-missing-number
0383-ransom-note
0387-first-unique-character-in-a-string
0438-find-all-anagrams-in-a-string
0448-find-all-numbers-disappeared-in-an-array
0451-sort-characters-by-frequency
0496-next-greater-element-i
0560-subarray-sum-equals-k	Medium
0567-permutation-in-string
0645-set-mismatch
0653-two-sum-iv-input-is-a-bst	Easy
0690-employee-importance	Medium
0781-rabbits-in-forest	Medium
0811-subdomain-visit-count	Medium
0974-subarray-sums-divisible-by-k	Medium
1365-how-many-numbers-are-smaller-than-the-current-number
1590-make-sum-divisible-by-p
1752-arithmetic-subarrays
1798-max-number-of-k-sum-pairs
1987-substrings-of-size-three-with-distinct-characters
2526-find-consecutive-integers-from-a-data-stream
2540-minimum-common-value
2581-divide-players-into-teams-of-equal-skill
3043-find-the-length-of-the-longest-common-prefix

Divide and Conquer

Problem Name	Difficulty
0053-maximum-subarray	Medium
0169-majority-element

Sorting

Problem Name	Difficulty
0056-merge-intervals
0169-majority-element
0179-largest-number	Medium
0217-contains-duplicate
0229-majority-element-ii
0268-missing-number
0451-sort-characters-by-frequency
0455-assign-cookies
0645-set-mismatch
0917-boats-to-save-people
0976-largest-perimeter-triangle	Easy
1029-two-city-scheduling	Medium
1365-how-many-numbers-are-smaller-than-the-current-number
1752-arithmetic-subarrays
1798-max-number-of-k-sum-pairs
2581-divide-players-into-teams-of-equal-skill
2824-count-pairs-whose-sum-is-less-than-target

Counting

Problem Name	Difficulty
0169-majority-element
0229-majority-element-ii
0383-ransom-note
0387-first-unique-character-in-a-string
0451-sort-characters-by-frequency
0811-subdomain-visit-count	Medium
1987-substrings-of-size-three-with-distinct-characters
2526-find-consecutive-integers-from-a-data-stream

Binary Search

Problem Name	Difficulty
0034-find-first-and-last-position-of-element-in-sorted-array
0035-search-insert-position
0153-find-minimum-in-rotated-sorted-array
0167-two-sum-ii-input-array-is-sorted
0268-missing-number
0278-first-bad-version
0792-binary-search
0907-koko-eating-bananas
1011-capacity-to-ship-packages-within-d-days
1056-capacity-to-ship-packages-within-d-days
1646-kth-missing-positive-number
2540-minimum-common-value
2824-count-pairs-whose-sum-is-less-than-target

Bit Manipulation

Problem Name	Difficulty
0067-add-binary
0078-subsets	Medium
0268-missing-number
0342-power-of-four	Easy
0645-set-mismatch
2305-fair-distribution-of-cookies	Medium
3191-minimum-operations-to-make-binary-array-elements-equal-to-one-i	Medium

Queue

Problem Name	Difficulty
0225-implement-stack-using-queues
0232-implement-queue-using-stacks
0387-first-unique-character-in-a-string
0641-design-circular-deque	Medium
0933-number-of-recent-calls
2526-find-consecutive-integers-from-a-data-stream
3191-minimum-operations-to-make-binary-array-elements-equal-to-one-i	Medium

Stack

Problem Name	Difficulty
0020-valid-parentheses
0071-simplify-path	Medium
0094-binary-tree-inorder-traversal
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0155-min-stack
0224-basic-calculator
0225-implement-stack-using-queues
0232-implement-queue-using-stacks
0234-palindrome-linked-list
0496-next-greater-element-i
0682-baseball-game
0739-daily-temperatures
0844-backspace-string-compare
0856-score-of-parentheses	Medium
1441-build-an-array-with-stack-operations	Medium
1472-design-browser-history	Medium
1598-crawler-log-folder	Easy
2000-reverse-prefix-of-word
2390-removing-stars-from-a-string	Medium
2487-remove-nodes-from-linked-list	Medium
3174-clear-digits

Greedy

Problem Name	Difficulty
0055-jump-game	Medium
0179-largest-number	Medium
0330-patching-array
0455-assign-cookies
0781-rabbits-in-forest	Medium
0860-lemonade-change	Easy
0917-boats-to-save-people
0976-largest-perimeter-triangle	Easy
1029-two-city-scheduling	Medium

Sliding Window

Problem Name	Difficulty
0076-minimum-window-substring
0219-contains-duplicate-ii
0438-find-all-anagrams-in-a-string
0567-permutation-in-string
0643-maximum-average-subarray-i
1987-substrings-of-size-three-with-distinct-characters
3191-minimum-operations-to-make-binary-array-elements-equal-to-one-i	Medium

Prefix Sum

Problem Name	Difficulty
0238-product-of-array-except-self
0304-range-sum-query-2d-immutable	Medium
0560-subarray-sum-equals-k	Medium
0974-subarray-sums-divisible-by-k	Medium
1413-minimum-value-to-get-positive-step-by-step-sum	Easy
1480-running-sum-of-1d-array
1590-make-sum-divisible-by-p
2102-find-the-middle-index-in-array
2465-shifting-letters-ii
3191-minimum-operations-to-make-binary-array-elements-equal-to-one-i	Medium

Dynamic Programming

Problem Name	Difficulty
0053-maximum-subarray	Medium
0055-jump-game	Medium
0118-pascals-triangle
0486-predict-the-winner	Medium
0509-fibonacci-number	Easy
2305-fair-distribution-of-cookies	Medium

Combinatorics

Problem Name	Difficulty
2324-find-triangular-sum-of-an-array

Counting Sort

Problem Name	Difficulty
1365-how-many-numbers-are-smaller-than-the-current-number

Heap (Priority Queue)

Problem Name	Difficulty
0451-sort-characters-by-frequency

Bucket Sort

Problem Name	Difficulty
0451-sort-characters-by-frequency

Interactive

Problem Name	Difficulty
0278-first-bad-version

Monotonic Stack

Problem Name	Difficulty
0496-next-greater-element-i
0739-daily-temperatures
2487-remove-nodes-from-linked-list	Medium

Tree

Problem Name	Difficulty
0094-binary-tree-inorder-traversal
0102-binary-tree-level-order-traversal	Medium
0104-maximum-depth-of-binary-tree	Easy
0111-minimum-depth-of-binary-tree	Easy
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0226-invert-binary-tree	Easy
0572-subtree-of-another-tree	Easy
0653-two-sum-iv-input-is-a-bst	Easy
0690-employee-importance	Medium

Depth-First Search

Problem Name	Difficulty
0094-binary-tree-inorder-traversal
0104-maximum-depth-of-binary-tree	Easy
0111-minimum-depth-of-binary-tree	Easy
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0226-invert-binary-tree	Easy
0547-number-of-provinces	Medium
0572-subtree-of-another-tree	Easy
0653-two-sum-iv-input-is-a-bst	Easy
0690-employee-importance	Medium
0841-keys-and-rooms	Medium
1971-find-if-path-exists-in-graph	Easy

Binary Tree

Problem Name	Difficulty
0094-binary-tree-inorder-traversal
0102-binary-tree-level-order-traversal	Medium
0104-maximum-depth-of-binary-tree	Easy
0111-minimum-depth-of-binary-tree	Easy
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0226-invert-binary-tree	Easy
0572-subtree-of-another-tree	Easy
0653-two-sum-iv-input-is-a-bst	Easy

Linked List

Problem Name	Difficulty
0203-remove-linked-list-elements	Easy
0234-palindrome-linked-list
0328-odd-even-linked-list	Medium
0641-design-circular-deque	Medium
0707-design-linked-list	Medium
1472-design-browser-history	Medium
2487-remove-nodes-from-linked-list	Medium

Recursion

Problem Name	Difficulty
0203-remove-linked-list-elements	Easy
0224-basic-calculator
0234-palindrome-linked-list
0342-power-of-four	Easy
0486-predict-the-winner	Medium
0509-fibonacci-number	Easy
1922-count-good-numbers	Medium
2487-remove-nodes-from-linked-list	Medium

Design

Problem Name	Difficulty
0155-min-stack
0225-implement-stack-using-queues
0232-implement-queue-using-stacks
0304-range-sum-query-2d-immutable	Medium
0641-design-circular-deque	Medium
0707-design-linked-list	Medium
0933-number-of-recent-calls
1472-design-browser-history	Medium
2526-find-consecutive-integers-from-a-data-stream

Data Stream

Problem Name	Difficulty
0933-number-of-recent-calls
1472-design-browser-history	Medium
2526-find-consecutive-integers-from-a-data-stream

Number Theory

Problem Name	Difficulty
2413-smallest-even-multiple

Trie

Problem Name	Difficulty
0014-longest-common-prefix
3043-find-the-length-of-the-longest-common-prefix

Matrix

Problem Name	Difficulty
0304-range-sum-query-2d-immutable	Medium
0661-image-smoother	Easy

Doubly-Linked List

Problem Name	Difficulty
1472-design-browser-history	Medium

Breadth-First Search

Problem Name	Difficulty
0102-binary-tree-level-order-traversal	Medium
0104-maximum-depth-of-binary-tree	Easy
0111-minimum-depth-of-binary-tree	Easy
0226-invert-binary-tree	Easy
0547-number-of-provinces	Medium
0653-two-sum-iv-input-is-a-bst	Easy
0690-employee-importance	Medium
0841-keys-and-rooms	Medium
1971-find-if-path-exists-in-graph	Easy

Union-Find

Problem Name	Difficulty
0547-number-of-provinces	Medium
1971-find-if-path-exists-in-graph	Easy

Graph Theory

Problem Name	Difficulty
0547-number-of-provinces	Medium
0841-keys-and-rooms	Medium
1791-find-center-of-star-graph	Easy
1971-find-if-path-exists-in-graph	Easy

Memoization

Problem Name	Difficulty
0509-fibonacci-number	Easy

Game Theory

Problem Name	Difficulty
0486-predict-the-winner	Medium

Backtracking

Problem Name	Difficulty
0051-n-queens	Hard
0052-n-queens-ii	Hard
0077-combinations	Medium
0078-subsets	Medium
2305-fair-distribution-of-cookies	Medium

String Matching

Problem Name	Difficulty
0572-subtree-of-another-tree	Easy

Hash Function

Problem Name	Difficulty
0572-subtree-of-another-tree	Easy

Binary Search Tree

Problem Name	Difficulty
0653-two-sum-iv-input-is-a-bst	Easy

Bitmask

Problem Name	Difficulty
2305-fair-distribution-of-cookies	Medium