Leetcode

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

Tree

0098-validate-binary-search-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
0450-delete-node-in-a-bst
0617-merge-two-binary-trees
0653-two-sum-iv-input-is-a-bst
0783-search-in-a-binary-search-tree
0784-insert-into-a-binary-search-tree

Depth-First Search

0098-validate-binary-search-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
0547-number-of-provinces
0617-merge-two-binary-trees
0653-two-sum-iv-input-is-a-bst

Binary Tree

0098-validate-binary-search-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
0450-delete-node-in-a-bst
0617-merge-two-binary-trees
0653-two-sum-iv-input-is-a-bst
0783-search-in-a-binary-search-tree
0784-insert-into-a-binary-search-tree

Breadth-First Search

0547-number-of-provinces
0617-merge-two-binary-trees
0653-two-sum-iv-input-is-a-bst

Binary Search Tree

0098-validate-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
0653-two-sum-iv-input-is-a-bst
0783-search-in-a-binary-search-tree
0784-insert-into-a-binary-search-tree
1476-count-negative-numbers-in-a-sorted-matrix

Hash Table

0653-two-sum-iv-input-is-a-bst

Two Pointers

0027-remove-element
0075-sort-colors
0088-merge-sorted-array
0653-two-sum-iv-input-is-a-bst

Array

0027-remove-element
0075-sort-colors
0088-merge-sorted-array
1137-height-checker
1476-count-negative-numbers-in-a-sorted-matrix
2148-minimum-number-of-moves-to-seat-everyone

Sorting

0075-sort-colors
0088-merge-sorted-array
1137-height-checker
2148-minimum-number-of-moves-to-seat-everyone

Counting Sort

1137-height-checker

Union Find

0547-number-of-provinces

Graph

0547-number-of-provinces

Greedy

2148-minimum-number-of-moves-to-seat-everyone

Math

0070-climbing-stairs

Dynamic Programming

0070-climbing-stairs

Memoization

0070-climbing-stairs

Matrix

1476-count-negative-numbers-in-a-sorted-matrix

LeetCode Topics

Array

0001-two-sum
0011-container-with-most-water
0033-search-in-rotated-sorted-array
0034-find-first-and-last-position-of-element-in-sorted-array
0035-search-insert-position
0048-rotate-image
0053-maximum-subarray
0063-unique-paths-ii
0064-minimum-path-sum
0073-set-matrix-zeroes
0074-search-a-2d-matrix
0075-sort-colors
0081-search-in-rotated-sorted-array-ii
0088-merge-sorted-array
0118-pascals-triangle
0119-pascals-triangle-ii
0121-best-time-to-buy-and-sell-stock
0122-best-time-to-buy-and-sell-stock-ii
0128-longest-consecutive-sequence
0152-maximum-product-subarray
0169-majority-element
0189-rotate-array
0198-house-robber
0209-minimum-size-subarray-sum
0215-kth-largest-element-in-an-array
0217-contains-duplicate
0219-contains-duplicate-ii
0238-product-of-array-except-self
0240-search-a-2d-matrix-ii
0268-missing-number
0283-move-zeroes
0287-find-the-duplicate-number
0300-longest-increasing-subsequence
0303-range-sum-query-immutable
0334-increasing-triplet-subsequence
0455-assign-cookies
0485-max-consecutive-ones
0525-contiguous-array
0560-subarray-sum-equals-k
0628-maximum-product-of-three-numbers
0747-min-cost-climbing-stairs
0792-binary-search
0861-flipping-an-image
0898-transpose-matrix
1293-three-consecutive-odds
1421-find-numbers-with-even-number-of-digits
1656-count-good-triplets
1786-count-the-number-of-consistent-strings
2265-partition-array-according-to-given-pivot
2271-rearrange-array-elements-by-sign
2277-count-equal-and-divisible-pairs-in-an-array
2626-count-the-number-of-good-subarrays
2856-count-complete-subarrays-in-an-array
2917-count-pairs-whose-sum-is-less-than-target
3213-count-subarrays-where-max-element-appears-at-least-k-times

Two Pointers

0005-longest-palindromic-substring
0011-container-with-most-water
0019-remove-nth-node-from-end-of-list
0028-find-the-index-of-the-first-occurrence-in-a-string
0075-sort-colors
0088-merge-sorted-array
0141-linked-list-cycle
0142-linked-list-cycle-ii
0151-reverse-words-in-a-string
0160-intersection-of-two-linked-lists
0189-rotate-array
0234-palindrome-linked-list
0283-move-zeroes
0287-find-the-duplicate-number
0455-assign-cookies
0861-flipping-an-image
0908-middle-of-the-linked-list
2265-partition-array-according-to-given-pivot
2271-rearrange-array-elements-by-sign
2917-count-pairs-whose-sum-is-less-than-target

Greedy

0011-container-with-most-water
0122-best-time-to-buy-and-sell-stock-ii
0334-increasing-triplet-subsequence
0455-assign-cookies
2032-largest-odd-number-in-string

Sorting

0075-sort-colors
0088-merge-sorted-array
0169-majority-element
0215-kth-largest-element-in-an-array
0217-contains-duplicate
0268-missing-number
0451-sort-characters-by-frequency
0455-assign-cookies
0628-maximum-product-of-three-numbers
2917-count-pairs-whose-sum-is-less-than-target

Math

0002-add-two-numbers
0048-rotate-image
0062-unique-paths
0189-rotate-array
0268-missing-number
0367-valid-perfect-square
0628-maximum-product-of-three-numbers
1013-fibonacci-number
1236-n-th-tribonacci-number
1421-find-numbers-with-even-number-of-digits
1500-count-largest-group
1642-water-bottles
2032-largest-odd-number-in-string
2556-convert-the-temperature
2998-count-symmetric-integers

Simulation

0861-flipping-an-image
0898-transpose-matrix
1642-water-bottles
2265-partition-array-according-to-given-pivot
2271-rearrange-array-elements-by-sign

Dynamic Programming

0005-longest-palindromic-substring
0053-maximum-subarray
0062-unique-paths
0063-unique-paths-ii
0064-minimum-path-sum
0118-pascals-triangle
0119-pascals-triangle-ii
0121-best-time-to-buy-and-sell-stock
0122-best-time-to-buy-and-sell-stock-ii
0152-maximum-product-subarray
0198-house-robber
0300-longest-increasing-subsequence
0338-counting-bits
0747-min-cost-climbing-stairs
1013-fibonacci-number
1236-n-th-tribonacci-number
1250-longest-common-subsequence

Memoization

1013-fibonacci-number
1236-n-th-tribonacci-number

Hash Table

0001-two-sum
0003-longest-substring-without-repeating-characters
0073-set-matrix-zeroes
0128-longest-consecutive-sequence
0141-linked-list-cycle
0142-linked-list-cycle-ii
0160-intersection-of-two-linked-lists
0169-majority-element
0217-contains-duplicate
0219-contains-duplicate-ii
0268-missing-number
0290-word-pattern
0451-sort-characters-by-frequency
0525-contiguous-array
0560-subarray-sum-equals-k
0920-uncommon-words-from-two-sentences
1500-count-largest-group
1786-count-the-number-of-consistent-strings
2626-count-the-number-of-good-subarrays
2856-count-complete-subarrays-in-an-array

Binary Search

0033-search-in-rotated-sorted-array
0034-find-first-and-last-position-of-element-in-sorted-array
0035-search-insert-position
0074-search-a-2d-matrix
0081-search-in-rotated-sorted-array-ii
0209-minimum-size-subarray-sum
0240-search-a-2d-matrix-ii
0268-missing-number
0287-find-the-duplicate-number
0300-longest-increasing-subsequence
0367-valid-perfect-square
0792-binary-search
2917-count-pairs-whose-sum-is-less-than-target

Bit Manipulation

0268-missing-number
0287-find-the-duplicate-number
0338-counting-bits
0476-number-complement
0861-flipping-an-image
1786-count-the-number-of-consistent-strings
2323-minimum-bit-flips-to-convert-number

Divide and Conquer

0053-maximum-subarray
0169-majority-element
0215-kth-largest-element-in-an-array
0240-search-a-2d-matrix-ii

Counting

0169-majority-element
0451-sort-characters-by-frequency
0920-uncommon-words-from-two-sentences
1786-count-the-number-of-consistent-strings

Matrix

0048-rotate-image
0063-unique-paths-ii
0064-minimum-path-sum
0073-set-matrix-zeroes
0074-search-a-2d-matrix
0240-search-a-2d-matrix-ii
0861-flipping-an-image
0898-transpose-matrix

Sliding Window

0003-longest-substring-without-repeating-characters
0209-minimum-size-subarray-sum
0219-contains-duplicate-ii
2626-count-the-number-of-good-subarrays
2856-count-complete-subarrays-in-an-array
3213-count-subarrays-where-max-element-appears-at-least-k-times

String

0003-longest-substring-without-repeating-characters
0005-longest-palindromic-substring
0014-longest-common-prefix
0028-find-the-index-of-the-first-occurrence-in-a-string
0038-count-and-say
0151-reverse-words-in-a-string
0290-word-pattern
0451-sort-characters-by-frequency
0812-rotate-string
0920-uncommon-words-from-two-sentences
1078-remove-outermost-parentheses
1250-longest-common-subsequence
1786-count-the-number-of-consistent-strings
2032-largest-odd-number-in-string
3207-make-three-strings-equal
3379-score-of-a-string

Stack

0234-palindrome-linked-list
1078-remove-outermost-parentheses

String Matching

0028-find-the-index-of-the-first-occurrence-in-a-string
0812-rotate-string

Heap (Priority Queue)

0215-kth-largest-element-in-an-array
0451-sort-characters-by-frequency

Bucket Sort

0451-sort-characters-by-frequency

Linked List

0002-add-two-numbers
0019-remove-nth-node-from-end-of-list
0141-linked-list-cycle
0142-linked-list-cycle-ii
0160-intersection-of-two-linked-lists
0206-reverse-linked-list
0234-palindrome-linked-list
0237-delete-node-in-a-linked-list
0908-middle-of-the-linked-list

Recursion

0002-add-two-numbers
0206-reverse-linked-list
0234-palindrome-linked-list
1013-fibonacci-number

Trie

0014-longest-common-prefix

Combinatorics

0062-unique-paths

Quickselect

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

Prefix Sum

0209-minimum-size-subarray-sum
0238-product-of-array-except-self
0303-range-sum-query-immutable
0525-contiguous-array
0560-subarray-sum-equals-k

Enumeration

1656-count-good-triplets
2998-count-symmetric-integers

Union Find

0128-longest-consecutive-sequence

Design

0303-range-sum-query-immutable