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

LeetCode Topics

Math

0002-add-two-numbers
0007-reverse-integer
0013-roman-to-integer
0048-rotate-image
0069-sqrtx
0189-rotate-array
0231-power-of-two
0263-ugly-number
0268-missing-number
0507-perfect-number
0556-next-greater-element-iii
1013-fibonacci-number
1014-k-closest-points-to-origin
1370-count-number-of-nice-subarrays
1925-count-nice-pairs-in-an-array
2032-largest-odd-number-in-string
2525-count-number-of-distinct-integers-after-reverse-operations
2595-smallest-value-after-replacing-with-sum-of-prime-factors
2609-distinct-prime-factors-of-product-of-array
2722-prime-in-diagonal
3567-convert-date-to-binary

Binary Search

0033-search-in-rotated-sorted-array
0034-find-first-and-last-position-of-element-in-sorted-array
0035-search-insert-position
0069-sqrtx
0081-search-in-rotated-sorted-array-ii
0162-find-peak-element
0209-minimum-size-subarray-sum
0240-search-a-2d-matrix-ii
0268-missing-number
0378-kth-smallest-element-in-a-sorted-matrix
0540-single-element-in-a-sorted-array
0658-find-k-closest-elements
0713-subarray-product-less-than-k
0792-binary-search
0882-peak-index-in-a-mountain-array
1046-max-consecutive-ones-iii
2394-count-subarrays-with-score-less-than-k
2469-longest-subsequence-with-limited-sum

Array

0001-two-sum
0014-longest-common-prefix
0026-remove-duplicates-from-sorted-array
0031-next-permutation
0033-search-in-rotated-sorted-array
0034-find-first-and-last-position-of-element-in-sorted-array
0035-search-insert-position
0048-rotate-image
0049-group-anagrams
0054-spiral-matrix
0059-spiral-matrix-ii
0073-set-matrix-zeroes
0075-sort-colors
0078-subsets
0081-search-in-rotated-sorted-array-ii
0088-merge-sorted-array
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
0119-pascals-triangle-ii
0121-best-time-to-buy-and-sell-stock
0128-longest-consecutive-sequence
0136-single-number
0137-single-number-ii
0162-find-peak-element
0169-majority-element
0189-rotate-array
0209-minimum-size-subarray-sum
0229-majority-element-ii
0238-product-of-array-except-self
0240-search-a-2d-matrix-ii
0268-missing-number
0283-move-zeroes
0303-range-sum-query-immutable
0347-top-k-frequent-elements
0378-kth-smallest-element-in-a-sorted-matrix
0455-assign-cookies
0485-max-consecutive-ones
0540-single-element-in-a-sorted-array
0560-subarray-sum-equals-k
0658-find-k-closest-elements
0713-subarray-product-less-than-k
0724-find-pivot-index
0792-binary-search
0860-design-circular-queue
0882-peak-index-in-a-mountain-array
0891-score-after-flipping-matrix
0987-reveal-cards-in-increasing-order
1014-k-closest-points-to-origin
1046-max-consecutive-ones-iii
1050-construct-binary-search-tree-from-preorder-traversal
1072-next-greater-node-in-linked-list
1127-last-stone-weight
1138-grumpy-bookstore-owner
1305-number-of-visible-people-in-a-queue
1319-unique-number-of-occurrences
1370-count-number-of-nice-subarrays
1445-number-of-sub-arrays-of-size-k-and-average-greater-than-or-equal-to-threshold
1570-final-prices-with-a-special-discount-in-a-shop
1586-longest-subarray-of-1s-after-deleting-one-element
1603-running-sum-of-1d-array
1741-sort-array-by-increasing-frequency
1798-max-number-of-k-sum-pairs
1802-number-of-students-unable-to-eat-lunch
1925-count-nice-pairs-in-an-array
1995-finding-pairs-with-a-certain-sum
2215-finding-3-digit-even-numbers
2271-rearrange-array-elements-by-sign
2394-count-subarrays-with-score-less-than-k
2469-longest-subsequence-with-limited-sum
2525-count-number-of-distinct-integers-after-reverse-operations
2609-distinct-prime-factors-of-product-of-array
2676-find-the-score-of-all-prefixes-of-an-array
2722-prime-in-diagonal
2847-find-maximum-number-of-string-pairs

Two Pointers

0019-remove-nth-node-from-end-of-list
0026-remove-duplicates-from-sorted-array
0031-next-permutation
0075-sort-colors
0086-partition-list
0088-merge-sorted-array
0125-valid-palindrome
0141-linked-list-cycle
0142-linked-list-cycle-ii
0143-reorder-list
0148-sort-list
0189-rotate-array
0234-palindrome-linked-list
0283-move-zeroes
0455-assign-cookies
0528-swapping-nodes-in-a-linked-list
0556-next-greater-element-iii
0658-find-k-closest-elements
0680-valid-palindrome-ii
0908-middle-of-the-linked-list
1798-max-number-of-k-sum-pairs
2216-delete-the-middle-node-of-a-linked-list
2271-rearrange-array-elements-by-sign

Hash Table

0001-two-sum
0013-roman-to-integer
0049-group-anagrams
0073-set-matrix-zeroes
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0106-construct-binary-tree-from-inorder-and-postorder-traversal
0128-longest-consecutive-sequence
0141-linked-list-cycle
0142-linked-list-cycle-ii
0169-majority-element
0205-isomorphic-strings
0229-majority-element-ii
0242-valid-anagram
0268-missing-number
0347-top-k-frequent-elements
0451-sort-characters-by-frequency
0560-subarray-sum-equals-k
1319-unique-number-of-occurrences
1370-count-number-of-nice-subarrays
1741-sort-array-by-increasing-frequency
1777-determine-if-two-strings-are-close
1798-max-number-of-k-sum-pairs
1925-count-nice-pairs-in-an-array
1995-finding-pairs-with-a-certain-sum
2215-finding-3-digit-even-numbers
2525-count-number-of-distinct-integers-after-reverse-operations
2609-distinct-prime-factors-of-product-of-array
2847-find-maximum-number-of-string-pairs

Divide and Conquer

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
0169-majority-element
0191-number-of-1-bits
0240-search-a-2d-matrix-ii
0347-top-k-frequent-elements
1014-k-closest-points-to-origin
1285-balance-a-binary-search-tree

Sorting

0049-group-anagrams
0075-sort-colors
0088-merge-sorted-array
0148-sort-list
0169-majority-element
0229-majority-element-ii
0242-valid-anagram
0268-missing-number
0347-top-k-frequent-elements
0378-kth-smallest-element-in-a-sorted-matrix
0451-sort-characters-by-frequency
0455-assign-cookies
0658-find-k-closest-elements
0987-reveal-cards-in-increasing-order
1014-k-closest-points-to-origin
1741-sort-array-by-increasing-frequency
1777-determine-if-two-strings-are-close
1798-max-number-of-k-sum-pairs
2215-finding-3-digit-even-numbers
2469-longest-subsequence-with-limited-sum

Counting

0169-majority-element
0229-majority-element-ii
0347-top-k-frequent-elements
0451-sort-characters-by-frequency
1777-determine-if-two-strings-are-close
1925-count-nice-pairs-in-an-array
2525-count-number-of-distinct-integers-after-reverse-operations

Greedy

0455-assign-cookies
0649-dota2-senate
0680-valid-palindrome-ii
0891-score-after-flipping-matrix
1285-balance-a-binary-search-tree
2032-largest-odd-number-in-string
2469-longest-subsequence-with-limited-sum

Sliding Window

0209-minimum-size-subarray-sum
0658-find-k-closest-elements
0713-subarray-product-less-than-k
1046-max-consecutive-ones-iii
1138-grumpy-bookstore-owner
1370-count-number-of-nice-subarrays
1445-number-of-sub-arrays-of-size-k-and-average-greater-than-or-equal-to-threshold
1586-longest-subarray-of-1s-after-deleting-one-element
2394-count-subarrays-with-score-less-than-k

Prefix Sum

0209-minimum-size-subarray-sum
0238-product-of-array-except-self
0303-range-sum-query-immutable
0560-subarray-sum-equals-k
0713-subarray-product-less-than-k
0724-find-pivot-index
1046-max-consecutive-ones-iii
1370-count-number-of-nice-subarrays
1603-running-sum-of-1d-array
2394-count-subarrays-with-score-less-than-k
2469-longest-subsequence-with-limited-sum
2576-minimum-penalty-for-a-shop
2676-find-the-score-of-all-prefixes-of-an-array

Linked List

0002-add-two-numbers
0019-remove-nth-node-from-end-of-list
0021-merge-two-sorted-lists
0083-remove-duplicates-from-sorted-list
0086-partition-list
0092-reverse-linked-list-ii
0114-flatten-binary-tree-to-linked-list
0141-linked-list-cycle
0142-linked-list-cycle-ii
0143-reorder-list
0148-sort-list
0206-reverse-linked-list
0234-palindrome-linked-list
0237-delete-node-in-a-linked-list
0528-swapping-nodes-in-a-linked-list
0860-design-circular-queue
0908-middle-of-the-linked-list
1072-next-greater-node-in-linked-list
1765-merge-in-between-linked-lists
2216-delete-the-middle-node-of-a-linked-list

Recursion

0002-add-two-numbers
0021-merge-two-sorted-lists
0143-reorder-list
0206-reverse-linked-list
0231-power-of-two
0234-palindrome-linked-list
1013-fibonacci-number

Merge Sort

0148-sort-list

Dynamic Programming

0118-pascals-triangle
0119-pascals-triangle-ii
0121-best-time-to-buy-and-sell-stock
1013-fibonacci-number
1586-longest-subarray-of-1s-after-deleting-one-element

Memoization

1013-fibonacci-number

Stack

0020-valid-parentheses
0094-binary-tree-inorder-traversal
0114-flatten-binary-tree-to-linked-list
0143-reorder-list
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0232-implement-queue-using-stacks
0234-palindrome-linked-list
1050-construct-binary-search-tree-from-preorder-traversal
1072-next-greater-node-in-linked-list
1078-remove-outermost-parentheses
1128-remove-all-adjacent-duplicates-in-string
1305-number-of-visible-people-in-a-queue
1570-final-prices-with-a-special-discount-in-a-shop
1737-maximum-nesting-depth-of-the-parentheses
1802-number-of-students-unable-to-eat-lunch

String

0008-string-to-integer-atoi
0013-roman-to-integer
0014-longest-common-prefix
0020-valid-parentheses
0049-group-anagrams
0125-valid-palindrome
0205-isomorphic-strings
0242-valid-anagram
0257-binary-tree-paths
0451-sort-characters-by-frequency
0556-next-greater-element-iii
0649-dota2-senate
0680-valid-palindrome-ii
0812-rotate-string
1078-remove-outermost-parentheses
1128-remove-all-adjacent-duplicates-in-string
1737-maximum-nesting-depth-of-the-parentheses
1777-determine-if-two-strings-are-close
2032-largest-odd-number-in-string
2576-minimum-penalty-for-a-shop
2847-find-maximum-number-of-string-pairs
3567-convert-date-to-binary

Monotonic Stack

1050-construct-binary-search-tree-from-preorder-traversal
1072-next-greater-node-in-linked-list
1305-number-of-visible-people-in-a-queue
1570-final-prices-with-a-special-discount-in-a-shop

Backtracking

0078-subsets
0113-path-sum-ii
0257-binary-tree-paths

Bit Manipulation

0078-subsets
0136-single-number
0137-single-number-ii
0191-number-of-1-bits
0231-power-of-two
0268-missing-number
0891-score-after-flipping-matrix
2323-minimum-bit-flips-to-convert-number

Queue

0232-implement-queue-using-stacks
0649-dota2-senate
0860-design-circular-queue
0987-reveal-cards-in-increasing-order
1802-number-of-students-unable-to-eat-lunch

Simulation

0054-spiral-matrix
0059-spiral-matrix-ii
0987-reveal-cards-in-increasing-order
1802-number-of-students-unable-to-eat-lunch
2271-rearrange-array-elements-by-sign
2595-smallest-value-after-replacing-with-sum-of-prime-factors
2847-find-maximum-number-of-string-pairs

Design

0232-implement-queue-using-stacks
0303-range-sum-query-immutable
0860-design-circular-queue
1995-finding-pairs-with-a-certain-sum

Tree

0094-binary-tree-inorder-traversal
0098-validate-binary-search-tree
0100-same-tree
0101-symmetric-tree
0102-binary-tree-level-order-traversal
0103-binary-tree-zigzag-level-order-traversal
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
0110-balanced-binary-tree
0112-path-sum
0113-path-sum-ii
0114-flatten-binary-tree-to-linked-list
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0199-binary-tree-right-side-view
0226-invert-binary-tree
0230-kth-smallest-element-in-a-bst
0235-lowest-common-ancestor-of-a-binary-search-tree
0236-lowest-common-ancestor-of-a-binary-tree
0257-binary-tree-paths
0437-path-sum-iii
0450-delete-node-in-a-bst
0538-convert-bst-to-greater-tree
0543-diameter-of-binary-tree
0783-search-in-a-binary-search-tree
0784-insert-into-a-binary-search-tree
1050-construct-binary-search-tree-from-preorder-traversal
1114-binary-search-tree-to-greater-sum-tree
1285-balance-a-binary-search-tree

Depth-First Search

0094-binary-tree-inorder-traversal
0098-validate-binary-search-tree
0100-same-tree
0101-symmetric-tree
0110-balanced-binary-tree
0112-path-sum
0113-path-sum-ii
0114-flatten-binary-tree-to-linked-list
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0199-binary-tree-right-side-view
0226-invert-binary-tree
0230-kth-smallest-element-in-a-bst
0235-lowest-common-ancestor-of-a-binary-search-tree
0236-lowest-common-ancestor-of-a-binary-tree
0257-binary-tree-paths
0437-path-sum-iii
0538-convert-bst-to-greater-tree
0543-diameter-of-binary-tree
1114-binary-search-tree-to-greater-sum-tree
1285-balance-a-binary-search-tree

Binary Tree

0094-binary-tree-inorder-traversal
0098-validate-binary-search-tree
0100-same-tree
0101-symmetric-tree
0102-binary-tree-level-order-traversal
0103-binary-tree-zigzag-level-order-traversal
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
0110-balanced-binary-tree
0112-path-sum
0113-path-sum-ii
0114-flatten-binary-tree-to-linked-list
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0199-binary-tree-right-side-view
0226-invert-binary-tree
0230-kth-smallest-element-in-a-bst
0235-lowest-common-ancestor-of-a-binary-search-tree
0236-lowest-common-ancestor-of-a-binary-tree
0257-binary-tree-paths
0437-path-sum-iii
0450-delete-node-in-a-bst
0538-convert-bst-to-greater-tree
0543-diameter-of-binary-tree
0783-search-in-a-binary-search-tree
0784-insert-into-a-binary-search-tree
1050-construct-binary-search-tree-from-preorder-traversal
1114-binary-search-tree-to-greater-sum-tree
1285-balance-a-binary-search-tree

Breadth-First Search

0100-same-tree
0101-symmetric-tree
0102-binary-tree-level-order-traversal
0103-binary-tree-zigzag-level-order-traversal
0112-path-sum
0199-binary-tree-right-side-view
0226-invert-binary-tree

Matrix

0048-rotate-image
0054-spiral-matrix
0059-spiral-matrix-ii
0073-set-matrix-zeroes
0240-search-a-2d-matrix-ii
0378-kth-smallest-element-in-a-sorted-matrix
0891-score-after-flipping-matrix
2722-prime-in-diagonal

Number Theory

2595-smallest-value-after-replacing-with-sum-of-prime-factors
2609-distinct-prime-factors-of-product-of-array
2722-prime-in-diagonal

Binary Search Tree

0098-validate-binary-search-tree
0108-convert-sorted-array-to-binary-search-tree
0230-kth-smallest-element-in-a-bst
0235-lowest-common-ancestor-of-a-binary-search-tree
0450-delete-node-in-a-bst
0538-convert-bst-to-greater-tree
0783-search-in-a-binary-search-tree
0784-insert-into-a-binary-search-tree
1050-construct-binary-search-tree-from-preorder-traversal
1114-binary-search-tree-to-greater-sum-tree
1285-balance-a-binary-search-tree

Enumeration

2215-finding-3-digit-even-numbers

Trie

0014-longest-common-prefix

String Matching

0812-rotate-string

Heap (Priority Queue)

0347-top-k-frequent-elements
0378-kth-smallest-element-in-a-sorted-matrix
0451-sort-characters-by-frequency
0658-find-k-closest-elements
1014-k-closest-points-to-origin
1127-last-stone-weight

Bucket Sort

0347-top-k-frequent-elements
0451-sort-characters-by-frequency

Quickselect

0347-top-k-frequent-elements
1014-k-closest-points-to-origin

Geometry

1014-k-closest-points-to-origin

Union Find

0128-longest-consecutive-sequence