Leetcode

Collection of LeetCode questions to ace the coding interview!

1. Data Structure
2. Blind75

LeetCode Topics

Hash Table

0001-two-sum
0049-group-anagrams
0128-longest-consecutive-sequence
0169-majority-element
0217-contains-duplicate
0219-contains-duplicate-ii
0242-valid-anagram
0290-word-pattern
0347-top-k-frequent-elements
0387-first-unique-character-in-a-string
0424-longest-repeating-character-replacement
0438-find-all-anagrams-in-a-string
0451-sort-characters-by-frequency
0532-k-diff-pairs-in-an-array
0535-encode-and-decode-tinyurl
0560-subarray-sum-equals-k
0965-unique-email-addresses
1112-find-words-that-can-be-formed-by-characters
1620-check-if-array-pairs-are-divisible-by-k

String

0020-valid-parentheses
0049-group-anagrams
0058-length-of-last-word
0125-valid-palindrome
0242-valid-anagram
0290-word-pattern
0387-first-unique-character-in-a-string
0392-is-subsequence
0424-longest-repeating-character-replacement
0438-find-all-anagrams-in-a-string
0451-sort-characters-by-frequency
0535-encode-and-decode-tinyurl
0680-valid-palindrome-ii
0965-unique-email-addresses
1112-find-words-that-can-be-formed-by-characters
1250-longest-common-subsequence
2346-largest-3-same-digit-number-in-string

Sorting

0015-3sum
0049-group-anagrams
0169-majority-element
0217-contains-duplicate
0242-valid-anagram
0347-top-k-frequent-elements
0451-sort-characters-by-frequency
0532-k-diff-pairs-in-an-array

Array

0001-two-sum
0011-container-with-most-water
0015-3sum
0049-group-anagrams
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
0128-longest-consecutive-sequence
0167-two-sum-ii-input-array-is-sorted
0169-majority-element
0217-contains-duplicate
0219-contains-duplicate-ii
0238-product-of-array-except-self
0347-top-k-frequent-elements
0532-k-diff-pairs-in-an-array
0560-subarray-sum-equals-k
0713-subarray-product-less-than-k
0932-monotonic-array
0954-maximum-sum-circular-subarray
0965-unique-email-addresses
1112-find-words-that-can-be-formed-by-characters
1231-replace-elements-with-greatest-element-on-right-side
1620-check-if-array-pairs-are-divisible-by-k
2058-concatenation-of-array
2195-time-needed-to-buy-tickets

Prefix Sum

0238-product-of-array-except-self
0560-subarray-sum-equals-k
0713-subarray-product-less-than-k

Sliding Window

0219-contains-duplicate-ii
0424-longest-repeating-character-replacement
0438-find-all-anagrams-in-a-string
0713-subarray-product-less-than-k

Divide and Conquer

0169-majority-element
0347-top-k-frequent-elements
0954-maximum-sum-circular-subarray

Heap (Priority Queue)

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

Bucket Sort

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

Counting

0169-majority-element
0347-top-k-frequent-elements
0387-first-unique-character-in-a-string
0451-sort-characters-by-frequency
1112-find-words-that-can-be-formed-by-characters
1620-check-if-array-pairs-are-divisible-by-k

Quickselect

0347-top-k-frequent-elements

Two Pointers

0011-container-with-most-water
0015-3sum
0125-valid-palindrome
0167-two-sum-ii-input-array-is-sorted
0392-is-subsequence
0532-k-diff-pairs-in-an-array
0680-valid-palindrome-ii

Stack

0020-valid-parentheses

Dynamic Programming

0070-climbing-stairs
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
0392-is-subsequence
0954-maximum-sum-circular-subarray
1250-longest-common-subsequence

Binary Search

0167-two-sum-ii-input-array-is-sorted
0532-k-diff-pairs-in-an-array
0713-subarray-product-less-than-k

Database

0183-customers-who-never-order
0584-find-customer-referee
0595-big-countries
0620-not-boring-movies
0627-swap-salary
1136-actors-and-directors-who-cooperated-at-least-three-times
1153-product-sales-analysis-i
1179-game-play-analysis-i
1245-user-activity-for-the-past-30-days-i
1258-article-views-i
1301-reformat-department-table
1509-replace-employee-id-with-the-unique-identifier
1541-top-travellers
1670-patients-with-a-condition
1811-fix-names-in-a-table
1827-invalid-tweets
1908-recyclable-and-low-fat-products
2024-calculate-special-bonus
2041-the-latest-login-in-2020

Union Find

0128-longest-consecutive-sequence

Greedy

0011-container-with-most-water
0122-best-time-to-buy-and-sell-stock-ii
0680-valid-palindrome-ii

Simulation

2058-concatenation-of-array
2195-time-needed-to-buy-tickets

Queue

0387-first-unique-character-in-a-string
0954-maximum-sum-circular-subarray
2195-time-needed-to-buy-tickets

Design

0535-encode-and-decode-tinyurl

Hash Function

0535-encode-and-decode-tinyurl

Monotonic Queue

0954-maximum-sum-circular-subarray

Math

0070-climbing-stairs

Memoization

0070-climbing-stairs

Linked List

0206-reverse-linked-list

Recursion

0206-reverse-linked-list