// PRACTICE

Problems

166 problems across 19 topics. Every count on this page is read from the database, so it cannot drift from what is actually tracked.

166

Total

Solved

35%

Complete

Easy

Medium

Hard

Editorials

Topics

To do 108

#1Two Sum○
easyhashingarrays
#20Valid Parentheses○
easystacks
#70Climbing Stairs○
easyrecursiondynamic programming
#136Single Number○
easybit manipulation
#190Reverse Bits○
easybit manipulation
#191Number of 1 Bits○
easybit manipulation
#228Summary Ranges○
easyintervals
#231Power of Two○
easyrecursionbit manipulation
#268Missing Number○
easyhashingarraysbit manipulation
#338Counting Bits○
easybit manipulationdynamic programming
#344Reverse String○
easyrecursionstringstwo pointers
#346Moving Average from Data Stream○
easyqueues
#383Ransom Note○
easyhashingstrings
#509Fibonacci Number○
easyrecursion
#703Kth Largest Element in a Stream○
easyheaps
#746Min Cost Climbing Stairs○
easydynamic programming
#771Jewels and Stones○
easyhashingstrings
#1133Largest Unique Number○
easyhashing
#1189Maximum Number of Balloons○
easyhashingstrings
#1323Maximum 69 Number○
easygreedy
#1426Counting Elements○
easyhashingarrays
#1710Maximum Units on a Truck○
easygreedy
#1832Check if the Sentence Is Pangram○
easyhashingstrings
#1971Find if Path Exists in Graph○
easygraphs
#2389Longest Subsequence With Limited Sum○
easybinary searcharrays
#17Letter Combinations of a Phone Number○
mediumbacktrackingstrings
#22Generate Parentheses○
mediumbacktrackingstrings
#39Combination Sum○
mediumbacktracking
#45Jump Game II○
mediumgreedy
#46Permutations○
mediumbacktracking
#50Pow(x, n)○
mediumrecursion
#55Jump Game○
mediumgreedy
#56Merge Intervals○
mediumintervals
#57Insert Interval○
mediumintervals
#63Unique Paths II○
mediumdynamic programmingarrays
#72Edit Distance○
mediumdynamic programmingstrings
#78Subsets○
mediumbacktracking
#79Word Search○
mediumbacktrackingarrays
#98Validate Binary Search Tree○
mediumtree
#133Clone Graph○
mediumgraphs
#134Gas Station○
mediumgreedy
#139Word Break○
mediumdynamic programmingstrings
#146LRU Cache○
mediumlinked listhashing
#155Min Stack○
mediumstacks
#198House Robber○
mediumdynamic programming
#200Number of Islands○
mediumgraphsarrays
#201Bitwise AND of Numbers Range○
mediumbit manipulation
#207Course Schedule○
mediumgraphs
#209Minimum Size Subarray Sum○
mediumarrayssliding window
#215Kth Largest Element in an Array○
mediumheapsarrays
#216Combination Sum III○
mediumbacktracking
#235Lowest Common Ancestor of BST○
mediumtree
#260Single Number III○
mediumbit manipulation
#309Best Time to Buy and Sell Stock with Cooldown○
mediumdynamic programmingarrays
#322Coin Change○
mediumdynamic programming
#347Top K Frequent Elements○
mediumhashingarrays
#371Sum of Two Integers○
mediumbit manipulation
#433Minimum Genetic Mutation○
mediumgraphs
#435Non-overlapping Intervals○
mediumgreedyintervals
#560Subarray Sum Equals K○
mediumarrayssliding windowhashing
#621Task Scheduler○
mediumheaps
#622Design Circular Queue○
mediumqueues
#647Palindromic Substrings○
mediumstringstwo pointers
#695Max Area of Island○
mediumgraphsarrays
#714Best Time to Buy and Sell Stock with Transaction Fee○
mediumdynamic programmingarrays
#739Daily Temperatures○
mediumstacks
#743Network Delay Time○
mediumgraphs
#779K-th Symbol in Grammar○
mediumrecursion
#787Cheapest Flights Within K Stops○
mediumgraphs
#797All Paths From Source to Target○
mediumbacktrackinggraphs
#904Fruit Into Baskets○
mediumarrayssliding window
#909Snakes and Ladders○
mediumgraphs
#930Binary Subarrays With Sum○
mediumarrayssliding window
#931Minimum Falling Path Sum○
mediumdynamic programmingarrays
#967Numbers With Same Consecutive Differences○
mediumbacktracking
#973K Closest Points to Origin○
mediumheapsarrays
#986Interval List Intersections○
mediumintervals
#1143Longest Common Subsequence○
mediumdynamic programmingstrings
#1167Minimum Cost to Connect Sticks○
mediumheaps
#1283Find the Smallest Divisor Given a Threshold○
mediumbinary search
#1288Remove Covered Intervals○
mediumintervals
#1306Jump Game III○
mediumgraphsarrays
#1338Reduce Array Size to The Half○
mediumgreedy
#1631Path With Minimum Effort○
mediumgraphsarrays
#1926Nearest Exit from Entrance in Maze○
mediumgraphsarrays
#1962Remove Stones to Minimize the Total○
mediumheapsarrays
#2101Detonate the Maximum Bombs○
mediumgraphsarrays
#2225Find Players With Zero or One Losses○
mediumhashingarrays
#gfg-first-one-binaryIndex of First 1 in Infinite Binary Array○
mediumsearching sorting
Approach
#gfg-infinite-sortedFind Position in Infinite Sorted Array○
mediumsearching sorting
Approach
#gfg-rotation-countRotation Count in Rotated Sorted Array○
mediumsearching sorting
Approach Solution
#37Sudoku Solver○
hardbacktracking
#51N-Queens○
hardbacktracking
#84Largest Rectangle in Histogram○
hardstacks
#124Binary Tree Maximum Path Sum○
hardtree
#127Word Ladder○
hardgraphsstrings
#135Candy○
hardgreedy
#164Maximum Gap○
hardsearching sorting
#239Sliding Window Maximum○
hardqueuesarrayssliding window
#295Find Median from Data Stream○
hardheaps
#297Serialize and Deserialize Binary Tree○
hardtree
#315Count of Smaller Numbers After Self○
hardsearching sorting
#340Longest Substring with At Most K Distinct Characters○
hardarrayssliding windowstrings
#410Split Array Largest Sum○
hardsearching sortingbinary search
#992Subarrays with K Different Integers○
hardarrayssliding window
#1004Max Consecutive Ones III○
hardarrayssliding window
#1248Count Number of Nice Subarrays○
hardarrayssliding window
#1851Minimum Interval to Include Each Query○
hardintervals

Solved 58

#14Longest Common Prefix✓
easystrings
Approach
#21Merge Two Sorted Lists✓
easylinked list
Editorial Approach
#35Search Insert Position✓
easysearching sortingbinary search
Approach
#88Merge Sorted Array✓
easysearching sortingarraystwo pointers
Solution
#100Same Tree✓
easytree
Editorial Approach
#101Symmetric Tree✓
easytree
Editorial Approach
#104Maximum Depth of Binary Tree✓
easytree
Editorial Approach
#121Best Time to Buy and Sell Stock✓
easyarrayssliding window
#125Valid Palindrome✓
easyarraystwo pointersstrings
#141Linked List Cycle✓
easylinked listtwo pointers
Editorial Approach
#169Majority Element✓
easysearching sortingarrays
Solution
#206Reverse Linked List✓
easylinked list
Editorial Approach
#226Invert Binary Tree✓
easytree
Editorial Approach
#242Valid Anagram✓
easystrings
#412Fizz Buzz✓
easystrings
Editorial Solution
#572Subtree of Another Tree✓
easytree
Editorial Approach
#704Binary Search✓
easysearching sortingbinary search
Solution
#744Find Smallest Letter Greater Than Target✓
easysearching sorting
Approach
#876Middle of the Linked List✓
easylinked listtwo pointers
Editorial Approach
#2Add Two Numbers✓
mediumlinked list
Editorial Approach
#3Longest Substring Without Repeating Characters✓
mediumarrayssliding windowstrings
Solution
#5Longest Palindromic Substring✓
mediumstringstwo pointers
#11Container With Most Water✓
mediumarraystwo pointers
#153Sum✓
mediumarraystwo pointers
#19Remove Nth Node From End of List✓
mediumlinked listtwo pointers
Editorial Approach
#33Search in Rotated Sorted Array✓
mediumsearching sortingbinary search
Solution
#34Find First and Last Position of Element in Sorted Array✓
mediumsearching sorting
Solution
#49Group Anagrams✓
mediumstringshashing
#74Search a 2D Matrix✓
mediumsearching sortingarrays
#75Sort Colors✓
mediumsearching sortingarraystwo pointers
Solution
#102Binary Tree Level Order Traversal✓
mediumtree
Editorial Approach
#103Binary Tree Zigzag Level Order Traversal✓
mediumtree
Editorial Approach
#110Balanced Binary Tree✓
mediumtree
Editorial Approach
#138Copy List with Random Pointer✓
mediumlinked list
Editorial Approach
#143Reorder List✓
mediumlinked listtwo pointers
Editorial Approach
#148Sort List✓
mediumsearching sortinglinked list
Solution
#153Find Minimum in Rotated Sorted Array✓
mediumsearching sortingbinary search
Solution
#162Find Peak Element✓
mediumsearching sortingbinary search
Solution
#167Two Sum II - Input Array Is Sorted✓
mediumarraystwo pointers
#179Largest Number✓
mediumsearching sortingarrays
Solution
#199Binary Tree Right Side View✓
mediumtree
Editorial Approach
#271Encode and Decode Strings✓
mediumstrings
Editorial Approach
#287Find the Duplicate Number✓
mediumlinked list
Editorial Approach
#424Longest Repeating Character Replacement✓
mediumarrayssliding windowstrings
#540Single Element in a Sorted Array✓
mediumsearching sorting
Solution
#567Permutation in String✓
mediumarrayssliding windowstrings
#852Peak Index in a Mountain Array✓
mediumsearching sortingbinary search
Solution
#875Koko Eating Bananas✓
mediumsearching sortingbinary search
#981Time Based Key-Value Store✓
mediumsearching sortingbinary search
#gfg-search-matrixSearch in Row-Column Sorted Matrix✓
mediumsearching sortingarrays
#4Median of Two Sorted Arrays✓
hardsearching sortingbinary search
Approach Solution
#23Merge k Sorted Lists✓
hardsearching sortinglinked listheaps
Editorial Approach
#25Reverse Nodes in K-Group✓
hardlinked list
Editorial Approach
#42Trapping Rain Water✓
hardarraystwo pointers
#68Text Justification✓
hardstrings
Approach
#76Minimum Window Substring✓
hardarrayssliding windowstrings
#1095Find in Mountain Array✓
hardsearching sortingbinary search
Solution
#gfg-allocate-pagesAllocate Minimum Pages✓
hardsearching sorting
Approach