Here is the list of the classified LeetCode core problems. It is useful for reviewing questions every time.

Binary Tree

• binary-tree-preorder-traversal
• binary-tree-inorder-traversal
• binary-tree-postorder-traversal
• binary-tree-level-order-traversal
• maximum-depth-of-binary-tree
• balanced-binary-tree
• binary-tree-maximum-path-sum
• lowest-common-ancestor-of-a-binary-tree
• binary-tree-level-order-traversal
• binary-tree-level-order-traversal-ii
• binary-tree-zigzag-level-order-traversal
• validate-binary-search-tree
• insert-into-a-binary-search-tree
• validate-binary-search-tree
• delete-node-in-a-bst

Linked List

• remove-duplicates-from-sorted-list
• remove-duplicates-from-sorted-list-ii
• reverse-linked-list
• reverse-linked-list-ii
• merge-two-sorted-lists
• partition-list
• sort-list
• reorder-list
• linked-list-cycle
• linked-list-cycle-ii
• palindrome-linked-list
• copy-list-with-random-pointer

Stack and Deque

• min-stack
• evaluate-reverse-polish-notation
• decode-string
• binary-tree-inorder-traversal
• clone-graph
• number-of-islands
• largest-rectangle-in-histogram
• implement-queue-using-stacks
• 01-matrix
• largest-rectangle-in-histogram
• trapping-rain-water
• sliding-window-maximum
• shortest-subarray-with-sum-at-least-k

Heap

• kth-largest-element-in-a-stream
• kth-smallest-element-in-a-sorted-matrix
• find-k-pairs-with-smallest-sums
• maximum-performance-of-a-team
• ipo
• meeting-rooms-ii
• reorganize-string
• minimum-risk-path
• network-delay-time
• cheapest-flights-within-k-stops

Union-Find (disjoint sets)

• redundant-connection
• accounts-merge
• longest-consecutive-sequence
• minimum-risk-path

Bitwise Operations

• single-number
• single-number-ii
• single-number-iii
• number-of-1-bits
• counting-bits
• reverse-bits
• bitwise-and-of-numbers-range

Binary Search

• search-for-range
• search-insert-position
• search-a-2d-matrix
• first-bad-version
• find-minimum-in-rotated-sorted-array
• find-minimum-in-rotated-sorted-array-ii
• search-in-rotated-sorted-array
• search-in-rotated-sorted-array-ii

Sort

• kth-largest-element-in-an-array
• top-k-frequent-elements
• sort-characters-by-frequency
• sort-colors

Dynamic Programming

• triangle
• minimum-path-sum
• unique-paths
• unique-paths-ii
• climbing-stairs
• jump-game
• jump-game-ii
• palindrome-partitioning-ii
• longest-increasing-subsequence
• word-break
• longest-common-subsequence
• edit-distance
• coin-change
• backpack
• backpack-ii
• maximum-product-subarray
• decode-ways
• best-time-to-buy-and-sell-stock-with-cooldown
• word-break-ii
• burst-balloons

Graph

• walls-and-gates
• shortest-bridge
• sliding-puzzle
• course-schedule-ii
• alien-dictionary
• sequence-reconstruction
• minimum-risk-path
• walls-and-gates
• shortest-bridge
• network-delay-time
• cheapest-flights-within-k-stops
• word-ladder

Recursion

• reverse-string
• swap-nodes-in-pairs
• unique-binary-search-trees-ii
• fibonacci-number

Slide Window

• minimum-window-substring
• permutation-in-string
• find-all-anagrams-in-a-string
• longest-substring-without-repeating-characters

Backtrack

• subsets
• subsets-ii
• permutations
• permutations-ii
• combination-sum
• letter-combinations-of-a-phone-number
• palindrome-partitioning
• restore-ip-addresses

Reference

1. algorithm-pattern
2. algorithm-pattern-python