LeetCode Topics

Array

Problem Name	Difficulty
0011-container-with-most-water
0015-3sum	Medium
0016-3sum-closest	Medium
0026-remove-duplicates-from-sorted-array
0033-search-in-rotated-sorted-array	Medium
0056-merge-intervals	Medium
0057-insert-interval	Medium
0074-search-a-2d-matrix	Medium
0075-sort-colors	Medium
0167-two-sum-ii-input-array-is-sorted
0209-minimum-size-subarray-sum
0217-contains-duplicate	Easy
0303-range-sum-query-immutable	Easy
0435-non-overlapping-intervals	Medium
0496-next-greater-element-i	Easy
0704-binary-search	Easy
0724-find-pivot-index	Easy
0874-walking-robot-simulation	Medium
1441-build-an-array-with-stack-operations	Medium
1470-shuffle-the-array
1929-concatenation-of-array
1991-find-the-middle-index-in-array	Easy
2270-number-of-ways-to-split-array	Medium
2461-maximum-sum-of-distinct-subarrays-with-length-k
2574-left-and-right-sum-differences	Easy

Two Pointers

Problem Name	Difficulty
0011-container-with-most-water
0015-3sum	Medium
0016-3sum-closest	Medium
0026-remove-duplicates-from-sorted-array
0075-sort-colors	Medium
0141-linked-list-cycle
0167-two-sum-ii-input-array-is-sorted
0202-happy-number
0876-middle-of-the-linked-list	Easy
0908-middle-of-the-linked-list
2095-delete-the-middle-node-of-a-linked-list	Medium

Binary Search

Problem Name	Difficulty
0033-search-in-rotated-sorted-array	Medium
0074-search-a-2d-matrix	Medium
0167-two-sum-ii-input-array-is-sorted
0209-minimum-size-subarray-sum
0704-binary-search	Easy

Greedy

Problem Name	Difficulty
0011-container-with-most-water
0435-non-overlapping-intervals	Medium

Hash Table

Problem Name	Difficulty
0003-longest-substring-without-repeating-characters
0141-linked-list-cycle
0202-happy-number
0217-contains-duplicate	Easy
0242-valid-anagram	Easy
0290-word-pattern	Easy
0496-next-greater-element-i	Easy
0874-walking-robot-simulation	Medium
2461-maximum-sum-of-distinct-subarrays-with-length-k

Linked List

Problem Name	Difficulty
0141-linked-list-cycle
0203-remove-linked-list-elements	Easy
0876-middle-of-the-linked-list	Easy
0908-middle-of-the-linked-list
2095-delete-the-middle-node-of-a-linked-list	Medium

Math

Problem Name	Difficulty
0202-happy-number

Simulation

Problem Name	Difficulty
0657-robot-return-to-origin	Easy
0874-walking-robot-simulation	Medium
1441-build-an-array-with-stack-operations	Medium
1929-concatenation-of-array

Sliding Window

Problem Name	Difficulty
0003-longest-substring-without-repeating-characters
0209-minimum-size-subarray-sum
2461-maximum-sum-of-distinct-subarrays-with-length-k

String

Problem Name	Difficulty
0003-longest-substring-without-repeating-characters
0020-valid-parentheses	Easy
0242-valid-anagram	Easy
0290-word-pattern	Easy
0657-robot-return-to-origin	Easy

Prefix Sum

Problem Name	Difficulty
0209-minimum-size-subarray-sum
0303-range-sum-query-immutable	Easy
0724-find-pivot-index	Easy
1991-find-the-middle-index-in-array	Easy
2270-number-of-ways-to-split-array	Medium
2574-left-and-right-sum-differences	Easy

Sorting

Problem Name	Difficulty
0015-3sum	Medium
0016-3sum-closest	Medium
0056-merge-intervals	Medium
0075-sort-colors	Medium
0217-contains-duplicate	Easy
0242-valid-anagram	Easy
0435-non-overlapping-intervals	Medium

Recursion

Problem Name	Difficulty
0203-remove-linked-list-elements	Easy

Dynamic Programming

Problem Name	Difficulty
0435-non-overlapping-intervals	Medium

Design

Problem Name	Difficulty
0303-range-sum-query-immutable	Easy

Matrix

Problem Name	Difficulty
0074-search-a-2d-matrix	Medium

Stack

Problem Name	Difficulty
0020-valid-parentheses	Easy
0496-next-greater-element-i	Easy
1441-build-an-array-with-stack-operations	Medium

Monotonic Stack

Problem Name	Difficulty
0496-next-greater-element-i	Easy