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

LeetCode Topics

Array

Problem Name	Difficulty
0033-search-in-rotated-sorted-array
0034-find-first-and-last-position-of-element-in-sorted-array
0039-combination-sum
0040-combination-sum-ii
0053-maximum-subarray
0063-unique-paths-ii
0064-minimum-path-sum
0066-plus-one
0075-sort-colors
0090-subsets-ii
0121-best-time-to-buy-and-sell-stock
0122-best-time-to-buy-and-sell-stock-ii
0123-best-time-to-buy-and-sell-stock-iii
0169-majority-element
0189-rotate-array
0198-house-robber
0240-search-a-2d-matrix-ii
0268-missing-number
0322-coin-change
0416-partition-equal-subset-sum
0485-max-consecutive-ones
0542-01-matrix
0560-subarray-sum-equals-k
0643-maximum-average-subarray-i
0724-find-pivot-index
0744-find-smallest-letter-greater-than-target
0944-delete-columns-to-make-sorted
0961-n-repeated-element-in-size-2n-array
0994-rotting-oranges
1018-binary-prefix-divisible-by-5
1020-number-of-enclaves
1109-corporate-flight-bookings
1200-minimum-absolute-difference
1262-greatest-sum-divisible-by-three
1266-minimum-time-visiting-all-points
1292-maximum-side-length-of-a-square-with-sum-less-than-or-equal-to-threshold
1351-count-negative-numbers-in-a-sorted-matrix
1390-four-divisors
1458-max-dot-product-of-two-subsequences
1480-running-sum-of-1d-array
1582-special-positions-in-a-binary-matrix
1877-minimize-maximum-pair-sum-in-array
1975-maximum-matrix-sum
1980-find-unique-binary-string
1984-minimum-difference-between-highest-and-lowest-of-k-scores
1991-find-the-middle-index-in-array
2054-two-best-non-overlapping-events
2110-number-of-smooth-descent-periods-of-a-stock
2149-rearrange-array-elements-by-sign
3010-divide-an-array-into-subarrays-with-minimum-cost-i
3013-divide-an-array-into-subarrays-with-minimum-cost-ii
3070-count-submatrices-with-top-left-element-and-sum-less-than-k
3212-count-submatrices-with-equal-frequency-of-x-and-y	Medium
3355-zero-array-transformation-i
3379-transformed-array
3432-count-partitions-with-even-sum-difference
3453-separate-squares-i
3531-count-covered-buildings
3567-minimum-absolute-difference-in-sliding-submatrix	Medium
3578-count-partitions-with-max-min-difference-at-most-k
3634-minimum-removals-to-balance-array
3640-trionic-array-ii
3719-longest-balanced-subarray-i
3721-longest-balanced-subarray-ii

Dynamic Programming

Problem Name	Difficulty
0022-generate-parentheses
0053-maximum-subarray
0062-unique-paths
0063-unique-paths-ii
0064-minimum-path-sum
0070-climbing-stairs
0072-edit-distance
0121-best-time-to-buy-and-sell-stock
0122-best-time-to-buy-and-sell-stock-ii
0123-best-time-to-buy-and-sell-stock-iii
0124-binary-tree-maximum-path-sum
0198-house-robber
0322-coin-change
0416-partition-equal-subset-sum
0516-longest-palindromic-subsequence
0542-01-matrix
0712-minimum-ascii-delete-sum-for-two-strings
0799-champagne-tower
1092-shortest-common-supersequence
1143-longest-common-subsequence
1262-greatest-sum-divisible-by-three
1458-max-dot-product-of-two-subsequences
1653-minimum-deletions-to-make-string-balanced
2054-two-best-non-overlapping-events
2110-number-of-smooth-descent-periods-of-a-stock
3578-count-partitions-with-max-min-difference-at-most-k
3640-trionic-array-ii

Greedy

Problem Name	Difficulty
0122-best-time-to-buy-and-sell-stock-ii
1262-greatest-sum-divisible-by-three
1382-balance-a-binary-search-tree
1877-minimize-maximum-pair-sum-in-array
1903-largest-odd-number-in-string
1975-maximum-matrix-sum
2600-k-items-with-the-maximum-sum

Sorting

Problem Name	Difficulty
0075-sort-colors
0169-majority-element
0268-missing-number
0295-find-median-from-data-stream
0389-find-the-difference
0761-special-binary-string
1200-minimum-absolute-difference
1262-greatest-sum-divisible-by-three
1877-minimize-maximum-pair-sum-in-array
1984-minimum-difference-between-highest-and-lowest-of-k-scores
2054-two-best-non-overlapping-events
3010-divide-an-array-into-subarrays-with-minimum-cost-i
3531-count-covered-buildings
3567-minimum-absolute-difference-in-sliding-submatrix	Medium
3634-minimum-removals-to-balance-array

Bit Manipulation

Problem Name	Difficulty
0067-add-binary
0090-subsets-ii
0190-reverse-bits
0268-missing-number
0389-find-the-difference
0401-binary-watch
0693-binary-number-with-alternating-bits
0762-prime-number-of-set-bits-in-binary-representation
0868-binary-gap
1009-complement-of-base-10-integer
1018-binary-prefix-divisible-by-5
1404-number-of-steps-to-reduce-a-number-in-binary-representation-to-one
1461-check-if-a-string-contains-all-binary-codes-of-size-k

Hash Table

Problem Name	Difficulty
0003-longest-substring-without-repeating-characters
0127-word-ladder
0141-linked-list-cycle
0169-majority-element
0268-missing-number
0389-find-the-difference
0560-subarray-sum-equals-k
0653-two-sum-iv-input-is-a-bst
0961-n-repeated-element-in-size-2n-array
1015-smallest-integer-divisible-by-k
1461-check-if-a-string-contains-all-binary-codes-of-size-k
1980-find-unique-binary-string
3013-divide-an-array-into-subarrays-with-minimum-cost-ii
3531-count-covered-buildings
3713-longest-balanced-substring-i
3714-longest-balanced-substring-ii
3719-longest-balanced-subarray-i
3721-longest-balanced-subarray-ii

Math

Problem Name	Difficulty
0050-powx-n
0062-unique-paths
0066-plus-one
0067-add-binary
0070-climbing-stairs
0189-rotate-array
0268-missing-number
0762-prime-number-of-set-bits-in-binary-representation
1015-smallest-integer-divisible-by-k
1266-minimum-time-visiting-all-points
1390-four-divisors
1523-count-odd-numbers-in-an-interval-range
1903-largest-odd-number-in-string
1925-count-square-sum-triples
2110-number-of-smooth-descent-periods-of-a-stock
2600-k-items-with-the-maximum-sum
3432-count-partitions-with-even-sum-difference

String

Problem Name	Difficulty
0003-longest-substring-without-repeating-characters
0020-valid-parentheses
0022-generate-parentheses
0067-add-binary
0072-edit-distance
0127-word-ladder
0389-find-the-difference
0516-longest-palindromic-subsequence
0712-minimum-ascii-delete-sum-for-two-strings
0761-special-binary-string
0944-delete-columns-to-make-sorted
1047-remove-all-adjacent-duplicates-in-string
1092-shortest-common-supersequence
1143-longest-common-subsequence
1404-number-of-steps-to-reduce-a-number-in-binary-representation-to-one
1461-check-if-a-string-contains-all-binary-codes-of-size-k
1545-find-kth-bit-in-nth-binary-string
1653-minimum-deletions-to-make-string-balanced
1758-minimum-changes-to-make-alternating-binary-string
1784-check-if-binary-string-has-at-most-one-segment-of-ones
1903-largest-odd-number-in-string
1980-find-unique-binary-string
2211-count-collisions-on-a-road
2483-minimum-penalty-for-a-shop
3713-longest-balanced-substring-i
3714-longest-balanced-substring-ii

Stack

Problem Name	Difficulty
0020-valid-parentheses
0155-min-stack
1047-remove-all-adjacent-duplicates-in-string
1653-minimum-deletions-to-make-string-balanced
2211-count-collisions-on-a-road

Simulation

Problem Name	Difficulty
0067-add-binary
1404-number-of-steps-to-reduce-a-number-in-binary-representation-to-one
1545-find-kth-bit-in-nth-binary-string
2149-rearrange-array-elements-by-sign
2211-count-collisions-on-a-road
3379-transformed-array

Prefix Sum

Problem Name	Difficulty
0560-subarray-sum-equals-k
0724-find-pivot-index
1109-corporate-flight-bookings
1292-maximum-side-length-of-a-square-with-sum-less-than-or-equal-to-threshold
1480-running-sum-of-1d-array
1991-find-the-middle-index-in-array
2483-minimum-penalty-for-a-shop
3070-count-submatrices-with-top-left-element-and-sum-less-than-k
3212-count-submatrices-with-equal-frequency-of-x-and-y	Medium
3355-zero-array-transformation-i
3432-count-partitions-with-even-sum-difference
3578-count-partitions-with-max-min-difference-at-most-k
3714-longest-balanced-substring-ii
3719-longest-balanced-subarray-i
3721-longest-balanced-subarray-ii

Queue

Problem Name	Difficulty
3578-count-partitions-with-max-min-difference-at-most-k

Sliding Window

Problem Name	Difficulty
0003-longest-substring-without-repeating-characters
0643-maximum-average-subarray-i
1984-minimum-difference-between-highest-and-lowest-of-k-scores
3013-divide-an-array-into-subarrays-with-minimum-cost-ii
3578-count-partitions-with-max-min-difference-at-most-k
3634-minimum-removals-to-balance-array

Monotonic Queue

Problem Name	Difficulty
3578-count-partitions-with-max-min-difference-at-most-k

Enumeration

Problem Name	Difficulty
1925-count-square-sum-triples
3010-divide-an-array-into-subarrays-with-minimum-cost-i
3713-longest-balanced-substring-i

Linked List

Problem Name	Difficulty
0141-linked-list-cycle
0206-reverse-linked-list
0237-delete-node-in-a-linked-list
0876-middle-of-the-linked-list

Two Pointers

Problem Name	Difficulty
0075-sort-colors
0141-linked-list-cycle
0189-rotate-array
0295-find-median-from-data-stream
0653-two-sum-iv-input-is-a-bst
0876-middle-of-the-linked-list
1877-minimize-maximum-pair-sum-in-array
2149-rearrange-array-elements-by-sign

Recursion

Problem Name	Difficulty
0050-powx-n
0206-reverse-linked-list
1545-find-kth-bit-in-nth-binary-string

Binary Search

Problem Name	Difficulty
0033-search-in-rotated-sorted-array
0034-find-first-and-last-position-of-element-in-sorted-array
0240-search-a-2d-matrix-ii
0268-missing-number
0744-find-smallest-letter-greater-than-target
1292-maximum-side-length-of-a-square-with-sum-less-than-or-equal-to-threshold
1351-count-negative-numbers-in-a-sorted-matrix
2054-two-best-non-overlapping-events
3453-separate-squares-i

Heap (Priority Queue)

Problem Name	Difficulty
0295-find-median-from-data-stream
2054-two-best-non-overlapping-events
3013-divide-an-array-into-subarrays-with-minimum-cost-ii

Matrix

Problem Name	Difficulty
0063-unique-paths-ii
0064-minimum-path-sum
0240-search-a-2d-matrix-ii
0542-01-matrix
0994-rotting-oranges
1020-number-of-enclaves
1292-maximum-side-length-of-a-square-with-sum-less-than-or-equal-to-threshold
1351-count-negative-numbers-in-a-sorted-matrix
1582-special-positions-in-a-binary-matrix
1975-maximum-matrix-sum
3070-count-submatrices-with-top-left-element-and-sum-less-than-k
3212-count-submatrices-with-equal-frequency-of-x-and-y	Medium
3567-minimum-absolute-difference-in-sliding-submatrix	Medium

Memoization

Problem Name	Difficulty
0070-climbing-stairs

Combinatorics

Problem Name	Difficulty
0062-unique-paths

Breadth-First Search

Problem Name	Difficulty
0100-same-tree
0101-symmetric-tree
0103-binary-tree-zigzag-level-order-traversal
0104-maximum-depth-of-binary-tree
0127-word-ladder
0322-coin-change
0542-01-matrix
0547-number-of-provinces
0653-two-sum-iv-input-is-a-bst
0994-rotting-oranges
1020-number-of-enclaves
1161-maximum-level-sum-of-a-binary-tree

Tree

Problem Name	Difficulty
0100-same-tree
0101-symmetric-tree
0103-binary-tree-zigzag-level-order-traversal
0104-maximum-depth-of-binary-tree
0110-balanced-binary-tree
0124-binary-tree-maximum-path-sum
0230-kth-smallest-element-in-a-bst
0236-lowest-common-ancestor-of-a-binary-tree
0543-diameter-of-binary-tree
0653-two-sum-iv-input-is-a-bst
0701-insert-into-a-binary-search-tree
1022-sum-of-root-to-leaf-binary-numbers
1161-maximum-level-sum-of-a-binary-tree
1382-balance-a-binary-search-tree

Depth-First Search

Problem Name	Difficulty
0100-same-tree
0101-symmetric-tree
0104-maximum-depth-of-binary-tree
0110-balanced-binary-tree
0124-binary-tree-maximum-path-sum
0230-kth-smallest-element-in-a-bst
0236-lowest-common-ancestor-of-a-binary-tree
0543-diameter-of-binary-tree
0547-number-of-provinces
0653-two-sum-iv-input-is-a-bst
1020-number-of-enclaves
1022-sum-of-root-to-leaf-binary-numbers
1161-maximum-level-sum-of-a-binary-tree
1382-balance-a-binary-search-tree

Binary Tree

Problem Name	Difficulty
0100-same-tree
0101-symmetric-tree
0103-binary-tree-zigzag-level-order-traversal
0104-maximum-depth-of-binary-tree
0110-balanced-binary-tree
0124-binary-tree-maximum-path-sum
0230-kth-smallest-element-in-a-bst
0236-lowest-common-ancestor-of-a-binary-tree
0543-diameter-of-binary-tree
0653-two-sum-iv-input-is-a-bst
0701-insert-into-a-binary-search-tree
1022-sum-of-root-to-leaf-binary-numbers
1161-maximum-level-sum-of-a-binary-tree
1382-balance-a-binary-search-tree

Geometry

Problem Name	Difficulty
1266-minimum-time-visiting-all-points

Divide and Conquer

Problem Name	Difficulty
0053-maximum-subarray
0169-majority-element
0190-reverse-bits
0240-search-a-2d-matrix-ii
0761-special-binary-string
1382-balance-a-binary-search-tree
3719-longest-balanced-subarray-i
3721-longest-balanced-subarray-ii

Counting

Problem Name	Difficulty
0169-majority-element
3713-longest-balanced-substring-i

Binary Search Tree

Problem Name	Difficulty
0230-kth-smallest-element-in-a-bst
0653-two-sum-iv-input-is-a-bst
0701-insert-into-a-binary-search-tree
1382-balance-a-binary-search-tree

Segment Tree

Problem Name	Difficulty
3719-longest-balanced-subarray-i
3721-longest-balanced-subarray-ii

Backtracking

Problem Name	Difficulty
0022-generate-parentheses
0039-combination-sum
0040-combination-sum-ii
0090-subsets-ii
0401-binary-watch
1980-find-unique-binary-string

Design

Problem Name	Difficulty
0155-min-stack
0295-find-median-from-data-stream

Union-Find

Problem Name	Difficulty
0547-number-of-provinces
1020-number-of-enclaves

Graph Theory

Problem Name	Difficulty
0547-number-of-provinces

Rolling Hash

Problem Name	Difficulty
1461-check-if-a-string-contains-all-binary-codes-of-size-k

Hash Function

Problem Name	Difficulty
1461-check-if-a-string-contains-all-binary-codes-of-size-k

Data Stream

Problem Name	Difficulty
0295-find-median-from-data-stream