LeetCode Top Interview 150

This is LeetCode’s official plan, and it differs from the community sheets in one important way: it includes the implementation problems the pattern-first sheets skip. Text Justification, Roman numerals, Simplify Path, Zigzag Conversion — unglamorous, no clever insight, purely careful code.

Those get asked. Not because they are interesting, but because they test whether you can write correct fiddly code under pressure, which is a real part of the job. A candidate who has only done pattern problems is often visibly thrown by them.

Use it if you have finished a pattern-first sheet and want to close that gap, or if you are targeting Microsoft or Bloomberg, where careful implementation is weighted more heavily than clever algorithms.

Track it here

Your progress is shared with every other list on this site — tick a problem off here and it is ticked off on its pattern page and in every other sheet that includes it. That is the point of tracking them in one place.

LeetCode Top Interview 150

by LeetCode (official study plan) · original sheet

150 problems

LeetCode's own plan. The most "interview-shaped" of the sheets — it includes the tedious-but-real implementation problems (Text Justification, Roman numerals, Simplify Path) that the pattern-first sheets skip.

150 problems

39 easy93 medium18 hard

AllEasyMediumHard

Unsolved onlyExportImportReset

▾Array / String · 2424

• ○88Merge Sorted Arrayeasy
• ○27Remove Elementeasy
• ○26Remove Duplicates from Sorted Arrayeasy
• ○80Remove Duplicates from Sorted Array IImedium
• ○169Majority Elementeasy
• ○189Rotate Arraymedium
• ○121Best Time to Buy and Sell Stockeasyamazonmetamicrosoftbloomberg
• ○122Best Time to Buy and Sell Stock IImedium
• ○55Jump Gamemedium
• ○45Jump Game IImedium
• ○274H-Indexmedium
• ○380Insert Delete GetRandom O(1)mediumamazonmetabloomberg
• ○238Product of Array Except Selfmediumamazonmetamicrosoftapple
• ○134Gas Stationmedium
• ○135Candyhard
• ○42Trapping Rain Waterhardamazongooglemetabloomberg
• ○13Roman to Integereasy
• ○12Integer to Romanmedium
• ○58Length of Last Wordeasy
• ○14Longest Common Prefixeasy
• ○151Reverse Words in a Stringmedium
• ○6Zigzag Conversionmedium
• ○28Find the Index of the First Occurrence in a Stringeasy
• ○68Text Justificationhard

▾Two Pointers · 55

• ○125Valid Palindromeeasy
• ○392Is Subsequenceeasy
• ○167Two Sum II - Input Array Is Sortedmedium
• ○11Container With Most Watermediumamazonmetabloomberg
• ○153Summediumamazonmetamicrosoftapplebloomberg

▾Sliding Window · 44

• ○209Minimum Size Subarray Summedium
• ○3Longest Substring Without Repeating Charactersmediumamazongooglemetamicrosoftbloomberg
• ○30Substring with Concatenation of All Wordshard
• ○76Minimum Window Substringhardmetaamazongoogleuber

▾Matrix · 55

• ○36Valid Sudokumedium
• ○54Spiral Matrixmedium
• ○48Rotate Imagemedium
• ○73Set Matrix Zeroesmedium
• ○289Game of Lifemedium

▾Hashmap · 99

• ○383Ransom Noteeasy
• ○205Isomorphic Stringseasy
• ○290Word Patterneasy
• ○242Valid Anagrameasyamazonmetabloomberg
• ○49Group Anagramsmediumamazonmetauberbloomberg
• ○1Two Sumeasyamazongooglemetamicrosoftapplebloomberg
• ○202Happy Numbereasy
• ○219Contains Duplicate IIeasy
• ○128Longest Consecutive Sequencemedium

▾Intervals · 44

• ○228Summary Rangeseasy
• ○56Merge Intervalsmediumgooglemetaamazonuberbloomberg
• ○57Insert Intervalmedium
• ○452Minimum Number of Arrows to Burst Balloonsmedium

▾Stack · 55

• ○20Valid Parentheseseasyamazongooglemetamicrosoftbloomberg
• ○71Simplify Pathmedium
• ○155Min Stackmedium
• ○150Evaluate Reverse Polish Notationmedium
• ○224Basic Calculatorhard

▾Linked List · 1111

• ○141Linked List Cycleeasyamazonmicrosoftbloomberg
• ○2Add Two Numbersmedium
• ○21Merge Two Sorted Listseasyamazonmicrosoftapplebloomberg
• ○138Copy List with Random Pointermediumamazonmicrosoftbloombergapple
• ○92Reverse Linked List IImedium
• ○25Reverse Nodes in k-Grouphard
• ○19Remove Nth Node From End of Listmedium
• ○82Remove Duplicates from Sorted List IImedium
• ○61Rotate Listmedium
• ○86Partition Listmedium
• ○146LRU Cachemediumamazonmicrosoftbloomberggoogleuber

▾Binary Tree General · 1414

• ○104Maximum Depth of Binary Treeeasy
• ○100Same Treeeasy
• ○226Invert Binary Treemedium
• ○101Symmetric Treeeasy
• ○105Construct Binary Tree from Preorder and Inorder Traversalmedium
• ○106Construct Binary Tree from Inorder and Postorder Traversalmedium
• ○117Populating Next Right Pointers in Each Node IImedium
• ○114Flatten Binary Tree to Linked Listmedium
• ○112Path Sumeasy
• ○129Sum Root to Leaf Numbersmedium
• ○124Binary Tree Maximum Path Sumhard
• ○173Binary Search Tree Iteratormedium
• ○222Count Complete Tree Nodeseasy
• ○236Lowest Common Ancestor of a Binary Treemediummetaamazonmicrosoftapple

▾Binary Tree BFS · 44

• ○199Binary Tree Right Side Viewmedium
• ○637Average of Levels in Binary Treeeasy
• ○102Binary Tree Level Order Traversalmediumamazonmetamicrosoftbytedance
• ○103Binary Tree Zigzag Level Order Traversalmedium

▾Binary Search Tree · 33

• ○530Minimum Absolute Difference in BSTeasy
• ○230Kth Smallest Element in a BSTmedium
• ○98Validate Binary Search Treemedium

▾Graph General · 66

• ○200Number of Islandsmediumamazongooglemetamicrosoftbytedance
• ○130Surrounded Regionsmedium
• ○133Clone Graphmediummetagoogleamazon
• ○399Evaluate Divisionmedium
• ○207Course Schedulemediumgoogleamazonmetabytedance
• ○210Course Schedule IImedium

▾Graph BFS · 33

• ○909Snakes and Laddersmedium
• ○433Minimum Genetic Mutationmedium
• ○127Word Ladderhardamazongooglebytedance

▾Trie · 33

• ○208Implement Trie (Prefix Tree)mediumgoogleamazonbloomberg
• ○211Design Add and Search Words Data Structuremedium
• ○212Word Search IIhardgoogleamazonbytedance

▾Backtracking · 77

• ○17Letter Combinations of a Phone Numbermedium
• ○77Combinationsmedium
• ○46Permutationsmedium
• ○39Combination Summedium
• ○52N-Queens IIhard
• ○22Generate Parenthesesmedium
• ○79Word Searchmedium

▾Divide & Conquer · 44

• ○108Convert Sorted Array to Binary Search Treeeasy
• ○148Sort Listmedium
• ○427Construct Quad Treemedium
• ○23Merge k Sorted Listshard

▾Kadane's Algorithm · 22

• ○53Maximum Subarraymediumamazonmicrosoftbloombergapple
• ○918Maximum Sum Circular Subarraymedium

▾Binary Search · 77

• ○35Search Insert Positioneasy
• ○74Search a 2D Matrixmedium
• ○162Find Peak Elementmedium
• ○33Search in Rotated Sorted Arraymediumamazonmetamicrosoftbloomberg
• ○34Find First and Last Position of Element in Sorted Arraymedium
• ○153Find Minimum in Rotated Sorted Arraymedium
• ○4Median of Two Sorted Arrayshardgoogleamazonmicrosoftbytedance

▾Heap · 44

• ○215Kth Largest Element in an Arraymedium
• ○502IPOhard
• ○373Find K Pairs with Smallest Sumsmedium
• ○295Find Median from Data Streamhardamazongooglemetabloomberg

▾Bit Manipulation · 66

• ○67Add Binaryeasy
• ○190Reverse Bitseasy
• ○191Number of 1 Bitseasy
• ○136Single Numbereasy
• ○137Single Number IImedium
• ○201Bitwise AND of Numbers Rangemedium

▾Math · 66

• ○9Palindrome Numbereasy
• ○66Plus Oneeasy
• ○172Factorial Trailing Zeroesmedium
• ○69Sqrt(x)easy
• ○50Pow(x, n)medium
• ○149Max Points on a Linehard

▾1D DP · 55

• ○70Climbing Stairseasy
• ○198House Robbermedium
• ○139Word Breakmediumgoogleamazonmetabytedance
• ○322Coin Changemediumamazongooglemicrosoftbytedance
• ○300Longest Increasing Subsequencemediumgooglemicrosoftbytedanceuber

▾Multidimensional DP · 99

• ○120Trianglemedium
• ○64Minimum Path Summedium
• ○63Unique Paths IImedium
• ○5Longest Palindromic Substringmedium
• ○97Interleaving Stringmedium
• ○72Edit Distancemediumgoogleamazonmicrosoftbytedance
• ○123Best Time to Buy and Sell Stock IIIhard
• ○188Best Time to Buy and Sell Stock IVhard
• ○221Maximal Squaremedium

Before you start this sheet

Do the consensus problems first. They are the problems every sheet author independently agreed on, so they are the highest-value problems available regardless of which sheet you eventually commit to.