5.Longest Palindromic Substring
MediumDynamic ProgrammingStringTwo Pointers38.7% acceptance81 companiesVideo
613 results
10.Regular Expression Matching
HardDynamic ProgrammingRecursionString31.8% acceptance25 companiesVideo
22.Generate Parentheses
MediumBacktrackingDynamic ProgrammingString79.6% acceptance40 companiesVideo
32.Longest Valid Parentheses
HardDynamic ProgrammingStackString41.2% acceptance25 companiesVideo
42.Trapping Rain Water
HardArrayDynamic ProgrammingMonotonic Stack68.2% acceptance73 companiesVideo
44.Wildcard Matching
HardDynamic ProgrammingGreedyRecursion32.8% acceptance17 companiesVideo
45.Jump Game II
MediumArrayDynamic ProgrammingGreedy43.2% acceptance26 companiesVideo
53.Maximum Subarray
MediumArrayDivide and ConquerDynamic Programming53.7% acceptance64 companiesVideo
55.Jump Game
MediumArrayDynamic ProgrammingGreedy41.2% acceptance33 companiesVideo
62.Unique Paths
MediumCombinatoricsDynamic ProgrammingMath67.3% acceptance21 companiesVideo
63.Unique Paths II
MediumArrayDynamic ProgrammingMatrix44.9% acceptance9 companiesVideo
64.Minimum Path Sum
MediumArrayDynamic ProgrammingMatrix68.6% acceptance17 companiesVideo
70.Climbing Stairs
EasyDynamic ProgrammingMathMemoization54.0% acceptance37 companiesVideo
72.Edit Distance
MediumDynamic ProgrammingString61.5% acceptance24 companiesVideo
85.Maximal Rectangle
HardArrayDynamic ProgrammingMatrix60.1% acceptance15 companiesVideo
87.Scramble String
HardDynamic ProgrammingString45.9% acceptance6 companiesVideo
91.Decode Ways
MediumDynamic ProgrammingString38.3% acceptance22 companiesVideo
95.Unique Binary Search Trees II
MediumBacktrackingBinary Search TreeBinary Tree63.3% acceptance5 companiesVideo
96.Unique Binary Search Trees
MediumBinary Search TreeBinary TreeDynamic Programming64.0% acceptance10 companiesVideo
97.Interleaving String
MediumDynamic ProgrammingString45.0% acceptance10 companiesVideo
115.Distinct Subsequences
HardDynamic ProgrammingString54.1% acceptance13 companiesVideo
118.Pascal's Triangle
EasyArrayDynamic Programming79.4% acceptance17 companiesVideo
119.Pascal's Triangle II
EasyArrayDynamic Programming67.8% acceptance6 companiesVideo
120.Triangle
MediumArrayDynamic Programming59.9% acceptance11 companiesVideo
121.Best Time to Buy and Sell Stock
EasyArrayDynamic Programming57.1% acceptance92 companiesVideo
122.Best Time to Buy and Sell Stock II
MediumArrayDynamic ProgrammingGreedy71.4% acceptance28 companiesVideo
123.Best Time to Buy and Sell Stock III
HardArrayDynamic Programming54.5% acceptance13 companiesVideo
124.Binary Tree Maximum Path Sum
HardBinary TreeDepth-First SearchDynamic Programming42.7% acceptance25 companiesVideo
131.Palindrome Partitioning
MediumBacktrackingDynamic ProgrammingString74.4% acceptance10 companiesVideo
132.Palindrome Partitioning II
HardDynamic ProgrammingString37.9% acceptance9 companiesVideo
139.Word Break
MediumArrayDynamic ProgrammingHash Table49.8% acceptance32 companiesVideo
140.Word Break II
HardArrayBacktrackingDynamic Programming56.4% acceptance16 companiesVideo
152.Maximum Product Subarray
MediumArrayDynamic Programming37.3% acceptance23 companiesVideo
174.Dungeon Game
HardArrayDynamic ProgrammingMatrix42.2% acceptance8 companiesVideo
188.Best Time to Buy and Sell Stock IV
HardArrayDynamic Programming51.5% acceptance11 companiesVideo
198.House Robber
MediumArrayDynamic Programming53.6% acceptance40 companiesVideo
213.House Robber II
MediumArrayDynamic Programming45.3% acceptance19 companiesVideo
221.Maximal Square
MediumArrayDynamic ProgrammingMatrix50.7% acceptance28 companiesVideo
233.Number of Digit One
HardDynamic ProgrammingMathRecursion39.9% acceptance6 companiesVideo
241.Different Ways to Add Parentheses
MediumDynamic ProgrammingMathMemoization73.7% acceptance6 companiesVideo
256.Paint House
MediumArrayDynamic Programming64.3% acceptance8 companiesPremium elsewhere, free hereVideo
264.Ugly Number II
MediumDynamic ProgrammingHash TableHeap (Priority Queue)49.7% acceptance9 companiesVideo
265.Paint House II
HardArrayDynamic Programming57.0% acceptance2 companiesPremium elsewhere, free hereVideo
276.Paint Fence
MediumDynamic Programming48.3% acceptance4 companiesPremium elsewhere, free hereVideo
279.Perfect Squares
MediumBreadth-First SearchDynamic ProgrammingMath57.0% acceptance12 companiesVideo
294.Flip Game II
MediumBacktrackingDynamic ProgrammingGame Theory52.2% acceptance2 companiesPremium elsewhere, free hereVideo
300.Longest Increasing Subsequence
MediumArrayBinary SearchDynamic Programming59.8% acceptance30 companiesVideo
309.Best Time to Buy and Sell Stock with Cooldown
MediumArrayDynamic Programming62.4% acceptance8 companiesVideo
312.Burst Balloons
HardArrayDynamic Programming64.3% acceptance15 companiesVideo
313.Super Ugly Number
MediumArrayDynamic ProgrammingMath46.6% acceptance5 companiesVideo
Showing 1–50 of 613
How to use these solutions
Each solution breaks the problem into approaches, usually from brute force to the best one, and explains why each works. Code comes in Python, Java, C++ and other languages. Knowing why an approach works matters more in an interview than remembering the code.
- Try the problem first. Give it at least 20 minutes before you open the solution.
- Read every approach. The brute force shows you the problem; the faster ones show the pattern.
- Check the complexity. Note the time and space of each approach and what makes the difference.
- Write it yourself. Close the solution and code it from memory in the editor.
- Come back in a week. Solving it again later is what makes the pattern stick.