LeetCode Topics

Array

0001-two-sum
0015-3sum
0018-4sum
0026-remove-duplicates-from-sorted-array
0027-remove-element
0031-next-permutation
0035-search-insert-position
0048-rotate-image
0053-maximum-subarray
0054-spiral-matrix
0056-merge-intervals
0066-plus-one
0073-set-matrix-zeroes
0075-sort-colors
0088-merge-sorted-array
0118-pascals-triangle
0121-best-time-to-buy-and-sell-stock
0128-longest-consecutive-sequence
0136-single-number
0152-maximum-product-subarray
0167-two-sum-ii-input-array-is-sorted
0169-majority-element
0189-rotate-array
0217-contains-duplicate
0229-majority-element-ii
0268-missing-number
0283-move-zeroes
0287-find-the-duplicate-number
0349-intersection-of-two-arrays
0350-intersection-of-two-arrays-ii
0414-third-maximum-number
0455-assign-cookies
0485-max-consecutive-ones
0493-reverse-pairs
0560-subarray-sum-equals-k
0628-maximum-product-of-three-numbers
0645-set-mismatch
0748-largest-number-at-least-twice-of-others
1421-find-numbers-with-even-number-of-digits
1878-check-if-array-is-sorted-and-rotated
1966-frequency-of-the-most-frequent-element
2271-rearrange-array-elements-by-sign
3227-find-missing-and-repeated-values
3321-type-of-triangle

Hash Table

0001-two-sum
0073-set-matrix-zeroes
0128-longest-consecutive-sequence
0160-intersection-of-two-linked-lists
0169-majority-element
0202-happy-number
0217-contains-duplicate
0229-majority-element-ii
0268-missing-number
0349-intersection-of-two-arrays
0350-intersection-of-two-arrays-ii
0560-subarray-sum-equals-k
0645-set-mismatch
3227-find-missing-and-repeated-values

Math

0009-palindrome-number
0048-rotate-image
0066-plus-one
0069-sqrtx
0189-rotate-array
0202-happy-number
0231-power-of-two
0268-missing-number
0326-power-of-three
0342-power-of-four
0628-maximum-product-of-three-numbers
1013-fibonacci-number
1421-find-numbers-with-even-number-of-digits
3172-divisible-and-non-divisible-sums-difference
3227-find-missing-and-repeated-values
3321-type-of-triangle

Two Pointers

0015-3sum
0018-4sum
0019-remove-nth-node-from-end-of-list
0026-remove-duplicates-from-sorted-array
0027-remove-element
0031-next-permutation
0075-sort-colors
0082-remove-duplicates-from-sorted-list-ii
0088-merge-sorted-array
0125-valid-palindrome
0160-intersection-of-two-linked-lists
0167-two-sum-ii-input-array-is-sorted
0189-rotate-array
0202-happy-number
0234-palindrome-linked-list
0283-move-zeroes
0287-find-the-duplicate-number
0349-intersection-of-two-arrays
0350-intersection-of-two-arrays-ii
0455-assign-cookies
0908-middle-of-the-linked-list
2271-rearrange-array-elements-by-sign

Sorting

0015-3sum
0018-4sum
0056-merge-intervals
0075-sort-colors
0088-merge-sorted-array
0169-majority-element
0217-contains-duplicate
0229-majority-element-ii
0268-missing-number
0349-intersection-of-two-arrays
0350-intersection-of-two-arrays-ii
0414-third-maximum-number
0455-assign-cookies
0628-maximum-product-of-three-numbers
0645-set-mismatch
0748-largest-number-at-least-twice-of-others
1966-frequency-of-the-most-frequent-element
3321-type-of-triangle

Linked List

0019-remove-nth-node-from-end-of-list
0021-merge-two-sorted-lists
0024-swap-nodes-in-pairs
0025-reverse-nodes-in-k-group
0082-remove-duplicates-from-sorted-list-ii
0083-remove-duplicates-from-sorted-list
0160-intersection-of-two-linked-lists
0203-remove-linked-list-elements
0206-reverse-linked-list
0234-palindrome-linked-list
0237-delete-node-in-a-linked-list
0908-middle-of-the-linked-list

String

0020-valid-parentheses
0125-valid-palindrome
3447-clear-digits

Stack

0020-valid-parentheses
0225-implement-stack-using-queues
0232-implement-queue-using-stacks
0234-palindrome-linked-list
3447-clear-digits

Recursion

0021-merge-two-sorted-lists
0024-swap-nodes-in-pairs
0025-reverse-nodes-in-k-group
0203-remove-linked-list-elements
0206-reverse-linked-list
0231-power-of-two
0234-palindrome-linked-list
0326-power-of-three
0342-power-of-four
1013-fibonacci-number

Binary Search

0035-search-insert-position
0069-sqrtx
0167-two-sum-ii-input-array-is-sorted
0268-missing-number
0287-find-the-duplicate-number
0349-intersection-of-two-arrays
0350-intersection-of-two-arrays-ii
0493-reverse-pairs
1966-frequency-of-the-most-frequent-element

Matrix

0048-rotate-image
0054-spiral-matrix
0073-set-matrix-zeroes
3227-find-missing-and-repeated-values

Divide and Conquer

0053-maximum-subarray
0169-majority-element
0493-reverse-pairs

Dynamic Programming

0053-maximum-subarray
0118-pascals-triangle
0121-best-time-to-buy-and-sell-stock
0152-maximum-product-subarray
1013-fibonacci-number

Simulation

0054-spiral-matrix
2271-rearrange-array-elements-by-sign
3447-clear-digits

Union Find

0128-longest-consecutive-sequence

Bit Manipulation

0136-single-number
0231-power-of-two
0268-missing-number
0287-find-the-duplicate-number
0342-power-of-four
0645-set-mismatch

Counting

0169-majority-element
0229-majority-element-ii

Design

0225-implement-stack-using-queues
0232-implement-queue-using-stacks

Queue

0225-implement-stack-using-queues
0232-implement-queue-using-stacks

Greedy

0455-assign-cookies
1966-frequency-of-the-most-frequent-element

Memoization

1013-fibonacci-number

Prefix Sum

0560-subarray-sum-equals-k
1966-frequency-of-the-most-frequent-element

Sliding Window

1966-frequency-of-the-most-frequent-element

Binary Indexed Tree

0493-reverse-pairs

Segment Tree

0493-reverse-pairs

Merge Sort

0493-reverse-pairs

Ordered Set

0493-reverse-pairs