Leetcode

Collection of LeetCode questions to ace the coding interview! - Created using LeetHub-3.0

LeetCode Topics

Array

Problem Name	Difficulty
0004-median-of-two-sorted-arrays	Hard
0229-majority-element-ii	Medium
0287-find-the-duplicate-number	Medium
0378-kth-smallest-element-in-a-sorted-matrix	Medium
0628-maximum-product-of-three-numbers	Easy
0692-top-k-frequent-words	Medium
0819-most-common-word	Easy
0832-flipping-an-image	Easy
0890-find-and-replace-pattern	Medium
0912-sort-an-array	Medium
1324-print-words-vertically	Medium
1588-sum-of-all-odd-length-subarrays	Easy
1662-check-if-two-string-arrays-are-equivalent	Easy
1700-number-of-students-unable-to-eat-lunch	Easy
1848-minimum-distance-to-the-target-element	Easy
1967-number-of-strings-that-appear-as-substrings-in-word	Easy
2109-adding-spaces-to-a-string	Medium
2176-count-equal-and-divisible-pairs-in-an-array	Easy
2248-intersection-of-multiple-arrays	Easy
2255-count-prefixes-of-a-given-string	Easy
2399-check-distances-between-same-letters	Easy
2562-find-the-array-concatenation-value	Easy
2586-count-the-number-of-vowel-strings-in-range	Easy
3079-find-the-sum-of-encrypted-integers	Easy
3861-minimum-capacity-box	Easy

String

Problem Name	Difficulty
0005-longest-palindromic-substring	Medium
0006-zigzag-conversion	Medium
0038-count-and-say	Medium
0043-multiply-strings	Medium
0065-valid-number	Hard
0290-word-pattern	Easy
0443-string-compression	Medium
0451-sort-characters-by-frequency	Medium
0647-palindromic-substrings	Medium
0692-top-k-frequent-words	Medium
0796-rotate-string	Easy
0819-most-common-word	Easy
0890-find-and-replace-pattern	Medium
0917-reverse-only-letters	Easy
1324-print-words-vertically	Medium
1455-check-if-a-word-occurs-as-a-prefix-of-any-word-in-a-sentence	Easy
1544-make-the-string-great	Easy
1576-replace-all-s-to-avoid-consecutive-repeating-characters	Easy
1662-check-if-two-string-arrays-are-equivalent	Easy
1957-delete-characters-to-make-fancy-string	Easy
1967-number-of-strings-that-appear-as-substrings-in-word	Easy
2027-minimum-moves-to-convert-string	Easy
2109-adding-spaces-to-a-string	Medium
2124-check-if-all-as-appears-before-all-bs	Easy
2243-calculate-digit-sum-of-a-string	Easy
2255-count-prefixes-of-a-given-string	Easy
2278-percentage-of-letter-in-string	Easy
2299-strong-password-checker-ii	Easy
2399-check-distances-between-same-letters	Easy
2490-circular-sentence	Easy
2586-count-the-number-of-vowel-strings-in-range	Easy
2839-check-if-strings-can-be-made-equal-with-operations-i	Easy
3274-check-if-two-chessboard-squares-have-the-same-color	Easy

Stack

Problem Name	Difficulty
0114-flatten-binary-tree-to-linked-list	Medium
0445-add-two-numbers-ii	Medium
1544-make-the-string-great	Easy
1700-number-of-students-unable-to-eat-lunch	Easy
2487-remove-nodes-from-linked-list	Medium

Queue

Problem Name	Difficulty
1700-number-of-students-unable-to-eat-lunch	Easy

Simulation

Problem Name	Difficulty
0043-multiply-strings	Medium
0832-flipping-an-image	Easy
1324-print-words-vertically	Medium
1700-number-of-students-unable-to-eat-lunch	Easy
2109-adding-spaces-to-a-string	Medium
2243-calculate-digit-sum-of-a-string	Easy
2562-find-the-array-concatenation-value	Easy

Two Pointers

Problem Name	Difficulty
0005-longest-palindromic-substring	Medium
0287-find-the-duplicate-number	Medium
0443-string-compression	Medium
0647-palindromic-substrings	Medium
0832-flipping-an-image	Easy
0917-reverse-only-letters	Easy
1455-check-if-a-word-occurs-as-a-prefix-of-any-word-in-a-sentence	Easy
1721-swapping-nodes-in-a-linked-list	Medium
2109-adding-spaces-to-a-string	Medium
2562-find-the-array-concatenation-value	Easy

String Matching

Problem Name	Difficulty
0796-rotate-string	Easy
1455-check-if-a-word-occurs-as-a-prefix-of-any-word-in-a-sentence	Easy

Hash Table

Problem Name	Difficulty
0229-majority-element-ii	Medium
0290-word-pattern	Easy
0451-sort-characters-by-frequency	Medium
0692-top-k-frequent-words	Medium
0819-most-common-word	Easy
0890-find-and-replace-pattern	Medium
2248-intersection-of-multiple-arrays	Easy
2399-check-distances-between-same-letters	Easy

Sorting

Problem Name	Difficulty
0229-majority-element-ii	Medium
0378-kth-smallest-element-in-a-sorted-matrix	Medium
0451-sort-characters-by-frequency	Medium
0628-maximum-product-of-three-numbers	Easy
0692-top-k-frequent-words	Medium
0912-sort-an-array	Medium
2248-intersection-of-multiple-arrays	Easy
3536-maximum-product-of-two-digits	Easy

Counting

Problem Name	Difficulty
0229-majority-element-ii	Medium
0451-sort-characters-by-frequency	Medium
0692-top-k-frequent-words	Medium
0819-most-common-word	Easy
2248-intersection-of-multiple-arrays	Easy
2586-count-the-number-of-vowel-strings-in-range	Easy

Math

Problem Name	Difficulty
0002-add-two-numbers	Medium
0007-reverse-integer	Medium
0009-palindrome-number	Easy
0043-multiply-strings	Medium
0445-add-two-numbers-ii	Medium
0628-maximum-product-of-three-numbers	Easy
1588-sum-of-all-odd-length-subarrays	Easy
2843-count-symmetric-integers	Easy
3079-find-the-sum-of-encrypted-integers	Easy
3274-check-if-two-chessboard-squares-have-the-same-color	Easy
3536-maximum-product-of-two-digits	Easy

Enumeration

Problem Name	Difficulty
2843-count-symmetric-integers	Easy

Greedy

Problem Name	Difficulty
2027-minimum-moves-to-convert-string	Easy

Linked List

Problem Name	Difficulty
0002-add-two-numbers	Medium
0114-flatten-binary-tree-to-linked-list	Medium
0445-add-two-numbers-ii	Medium
0707-design-linked-list	Medium
1721-swapping-nodes-in-a-linked-list	Medium
2487-remove-nodes-from-linked-list	Medium

Recursion

Problem Name	Difficulty
0002-add-two-numbers	Medium
2487-remove-nodes-from-linked-list	Medium

Monotonic Stack

Problem Name	Difficulty
2487-remove-nodes-from-linked-list	Medium

Design

Problem Name	Difficulty
0707-design-linked-list	Medium

Tree

Problem Name	Difficulty
0114-flatten-binary-tree-to-linked-list	Medium

Depth-First Search

Problem Name	Difficulty
0114-flatten-binary-tree-to-linked-list	Medium
0386-lexicographical-numbers	Medium

Binary Tree

Problem Name	Difficulty
0114-flatten-binary-tree-to-linked-list	Medium

Heap (Priority Queue)

Problem Name	Difficulty
0378-kth-smallest-element-in-a-sorted-matrix	Medium
0451-sort-characters-by-frequency	Medium
0692-top-k-frequent-words	Medium
0912-sort-an-array	Medium

Bucket Sort

Problem Name	Difficulty
0451-sort-characters-by-frequency	Medium
0692-top-k-frequent-words	Medium
0912-sort-an-array	Medium

Database

Problem Name	Difficulty
0184-department-highest-salary	Medium

Binary Search

Problem Name	Difficulty
0004-median-of-two-sorted-arrays	Hard
0287-find-the-duplicate-number	Medium
0378-kth-smallest-element-in-a-sorted-matrix	Medium

Divide and Conquer

Problem Name	Difficulty
0004-median-of-two-sorted-arrays	Hard
0912-sort-an-array	Medium

Dynamic Programming

Problem Name	Difficulty
0005-longest-palindromic-substring	Medium
0647-palindromic-substrings	Medium

Bit Manipulation

Problem Name	Difficulty
0287-find-the-duplicate-number	Medium
0832-flipping-an-image	Easy

Matrix

Problem Name	Difficulty
0378-kth-smallest-element-in-a-sorted-matrix	Medium
0832-flipping-an-image	Easy

Trie

Problem Name	Difficulty
0386-lexicographical-numbers	Medium
0692-top-k-frequent-words	Medium

Merge Sort

Problem Name	Difficulty
0912-sort-an-array	Medium

Radix Sort

Problem Name	Difficulty
0912-sort-an-array	Medium

Counting Sort

Problem Name	Difficulty
0912-sort-an-array	Medium

Prefix Sum

Problem Name	Difficulty
1588-sum-of-all-odd-length-subarrays	Easy

Boyer–Moore Majority Vote Algorithm

Problem Name	Difficulty
0229-majority-element-ii	Medium

Name		Name	Last commit message	Last commit date
Latest commit History 632 Commits
0002-add-two-numbers		0002-add-two-numbers
0003-longest-substring-without-repeating-characters		0003-longest-substring-without-repeating-characters
0004-median-of-two-sorted-arrays		0004-median-of-two-sorted-arrays
0005-longest-palindromic-substring		0005-longest-palindromic-substring
0006-zigzag-conversion		0006-zigzag-conversion
0007-reverse-integer		0007-reverse-integer
0009-palindrome-number		0009-palindrome-number
0013-roman-to-integer		0013-roman-to-integer
0019-remove-nth-node-from-end-of-list		0019-remove-nth-node-from-end-of-list
0020-valid-parentheses		0020-valid-parentheses
0028-find-the-index-of-the-first-occurrence-in-a-string		0028-find-the-index-of-the-first-occurrence-in-a-string
0038-count-and-say		0038-count-and-say
0043-multiply-strings		0043-multiply-strings
0065-valid-number		0065-valid-number
0066-plus-one		0066-plus-one
0083-remove-duplicates-from-sorted-list		0083-remove-duplicates-from-sorted-list
0094-binary-tree-inorder-traversal		0094-binary-tree-inorder-traversal
0100-same-tree		0100-same-tree
0102-binary-tree-level-order-traversal		0102-binary-tree-level-order-traversal
0104-maximum-depth-of-binary-tree		0104-maximum-depth-of-binary-tree
0114-flatten-binary-tree-to-linked-list		0114-flatten-binary-tree-to-linked-list
0128-longest-consecutive-sequence		0128-longest-consecutive-sequence
0129-sum-root-to-leaf-numbers		0129-sum-root-to-leaf-numbers
0141-linked-list-cycle		0141-linked-list-cycle
0144-binary-tree-preorder-traversal		0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal		0145-binary-tree-postorder-traversal
0151-reverse-words-in-a-string		0151-reverse-words-in-a-string
0184-department-highest-salary		0184-department-highest-salary
0203-remove-linked-list-elements		0203-remove-linked-list-elements
0205-isomorphic-strings		0205-isomorphic-strings
0208-implement-trie-prefix-tree		0208-implement-trie-prefix-tree
0222-count-complete-tree-nodes		0222-count-complete-tree-nodes
0225-implement-stack-using-queues		0225-implement-stack-using-queues
0229-majority-element-ii		0229-majority-element-ii
0232-implement-queue-using-stacks		0232-implement-queue-using-stacks
0237-delete-node-in-a-linked-list		0237-delete-node-in-a-linked-list
0263-ugly-number		0263-ugly-number
0278-first-bad-version		0278-first-bad-version
0287-find-the-duplicate-number		0287-find-the-duplicate-number
0290-word-pattern		0290-word-pattern
0342-power-of-four		0342-power-of-four
0347-top-k-frequent-elements		0347-top-k-frequent-elements
0378-kth-smallest-element-in-a-sorted-matrix		0378-kth-smallest-element-in-a-sorted-matrix
0386-lexicographical-numbers		0386-lexicographical-numbers
0404-sum-of-left-leaves		0404-sum-of-left-leaves
0443-string-compression		0443-string-compression
0445-add-two-numbers-ii		0445-add-two-numbers-ii
0450-delete-node-in-a-bst		0450-delete-node-in-a-bst
0451-sort-characters-by-frequency		0451-sort-characters-by-frequency
0501-find-mode-in-binary-search-tree		0501-find-mode-in-binary-search-tree
0509-fibonacci-number		0509-fibonacci-number
0520-detect-capital		0520-detect-capital
0530-minimum-absolute-difference-in-bst		0530-minimum-absolute-difference-in-bst
0551-student-attendance-record-i		0551-student-attendance-record-i
0561-array-partition		0561-array-partition
0628-maximum-product-of-three-numbers		0628-maximum-product-of-three-numbers
0647-palindromic-substrings		0647-palindromic-substrings
0692-top-k-frequent-words		0692-top-k-frequent-words
0701-insert-into-a-binary-search-tree		0701-insert-into-a-binary-search-tree
0706-design-hashmap		0706-design-hashmap
0707-design-linked-list		0707-design-linked-list
0728-self-dividing-numbers		0728-self-dividing-numbers
0783-minimum-distance-between-bst-nodes		0783-minimum-distance-between-bst-nodes
0796-rotate-string		0796-rotate-string
0819-most-common-word		0819-most-common-word
0832-flipping-an-image		0832-flipping-an-image
0844-backspace-string-compare		0844-backspace-string-compare
0890-find-and-replace-pattern		0890-find-and-replace-pattern
0912-sort-an-array		0912-sort-an-array
0917-reverse-only-letters		0917-reverse-only-letters
1002-find-common-characters		1002-find-common-characters
1324-print-words-vertically		1324-print-words-vertically
1331-rank-transform-of-an-array		1331-rank-transform-of-an-array
1374-generate-a-string-with-characters-that-have-odd-counts		1374-generate-a-string-with-characters-that-have-odd-counts
1385-find-the-distance-value-between-two-arrays		1385-find-the-distance-value-between-two-arrays
1399-count-largest-group		1399-count-largest-group
1408-string-matching-in-an-array		1408-string-matching-in-an-array
1455-check-if-a-word-occurs-as-a-prefix-of-any-word-in-a-sentence		1455-check-if-a-word-occurs-as-a-prefix-of-any-word-in-a-sentence
1523-count-odd-numbers-in-an-interval-range		1523-count-odd-numbers-in-an-interval-range
1539-kth-missing-positive-number		1539-kth-missing-positive-number
1544-make-the-string-great		1544-make-the-string-great
1576-replace-all-s-to-avoid-consecutive-repeating-characters		1576-replace-all-s-to-avoid-consecutive-repeating-characters
1588-sum-of-all-odd-length-subarrays		1588-sum-of-all-odd-length-subarrays
1608-special-array-with-x-elements-greater-than-or-equal-x		1608-special-array-with-x-elements-greater-than-or-equal-x
1636-sort-array-by-increasing-frequency		1636-sort-array-by-increasing-frequency
1662-check-if-two-string-arrays-are-equivalent		1662-check-if-two-string-arrays-are-equivalent
1669-merge-in-between-linked-lists		1669-merge-in-between-linked-lists
1700-number-of-students-unable-to-eat-lunch		1700-number-of-students-unable-to-eat-lunch
1716-calculate-money-in-leetcode-bank		1716-calculate-money-in-leetcode-bank
1721-swapping-nodes-in-a-linked-list		1721-swapping-nodes-in-a-linked-list
1752-check-if-array-is-sorted-and-rotated		1752-check-if-array-is-sorted-and-rotated
1768-merge-strings-alternately		1768-merge-strings-alternately
1790-check-if-one-string-swap-can-make-strings-equal		1790-check-if-one-string-swap-can-make-strings-equal
1796-second-largest-digit-in-a-string		1796-second-largest-digit-in-a-string
1816-truncate-sentence		1816-truncate-sentence
1822-sign-of-the-product-of-an-array		1822-sign-of-the-product-of-an-array
1844-replace-all-digits-with-characters		1844-replace-all-digits-with-characters
1848-minimum-distance-to-the-target-element		1848-minimum-distance-to-the-target-element
1877-minimize-maximum-pair-sum-in-array		1877-minimize-maximum-pair-sum-in-array
1880-check-if-word-equals-summation-of-two-words		1880-check-if-word-equals-summation-of-two-words

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Leetcode

LeetCode Topics

Array

String

Stack

Queue

Simulation

Two Pointers

String Matching

Hash Table

Sorting

Counting

Math

Enumeration

Greedy

Linked List

Recursion

Monotonic Stack

Design

Tree

Depth-First Search

Binary Tree

Heap (Priority Queue)

Bucket Sort

Database

Binary Search

Divide and Conquer

Dynamic Programming

Bit Manipulation

Matrix

Trie

Merge Sort

Radix Sort

Counting Sort

Prefix Sum

Boyer–Moore Majority Vote Algorithm

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