Array

How To: Aray

• 3 Sum [Two Pointers]
• 3 Sum closest [Two Pointers]
• 4 sum [Two pointer, Hash]
• Remove duplicates from sorted array [Two pointers]
• Remove element [Two pointers]
• Next permutation [Tricky]
• First missing positive [Tricky]
• Rotate image
• Spiral matrix [Simulation, Layer-by-Layer]
• Spiral matrix ii
• Plus one
• Set matrix zeroes
• Remove duplicates from sorted array II [Two Pointers]
• Pascals triangle
• Pascals triangle II
• Best time to buy and sell stock
• Longest consecutive sequence [BF, Sorting, Set -> Tricky]
• Read N characters given read4()
• Read N characters given read4() II [call multiple times]
• Missing ranges
• Majority element [Boyer-Moore Majority Vote Algorithm]
• Rotate array
• Minimum size subarray Sum [Binary Search]
• K-th largest element in an array
• Summary ranges
• Majority element II
• Product of array except self
• Search a 2D matrix II
• Shortest Word Distance
• Shortest Word Distance III
• Flatten 2D vector
• Find the Celebrity
• Game of life
• Flip game
• Best meeting point
• Sparse Matrix multiplication
• Increasing triplet subsequence
• Range addition
• Shuffle an array [EPI]
• Rotate function
• Fizz Buzz
• Third maximum number
• Battleships in a board
• Valid word square
• Find all duplicates in an array
• Find all numbers disappeared in an array
• Lonely pixel I
• Lonely pixel II
• Array nesting
• Reshape the matrix
• Shortest unsorted continuous subarray
• Can place flowers
• Maximum distance in arrays
• Maximum average subarray I [Math]
• Maximum average subarray II [Math]
• Image smoother
• Non decreasing array
• Beautiful arrangement II
• Maximum swap
• Longest continuous increasing subsequence
• K empty slots
• Degree of an array
• Subarray product less than K [Sliding window]
• 1 bit and 2 bit characters [Greedy]
• Candy crush
• Find pivot index
• My calendar I
• My calendar II
• My calendar III
• Largest number at least twice
• Pour water
• Toeplitz matrix
• Max chunks to make sorted II [Sliding Window]
• Max chunks to make sorted [Brute Force]
• Swim in rising water
• Number of matching subsequences
• Valid tic-tac-toe state
• Number of subarrays with bounded maximum
• Bricks falling when hit [Reverse Time and Union-Find]
• Max increase to keep city skyline [Row and Column Maximums]
• Shortest distance to a character [Min Array]
• Positions of large groups [Two Pointers]
• Flipping an image [Direct]
• Image overlap [Translate by Delta]
• Magic squares in grid [Brute Force]
• Split array into Fibonacci sequence [Brute Force]
• Longest mountain in array [Two Pointers]
• Maximize distance to closest person [Next Array]
• Lemonade change [Simulation]
• Transpose matrix [Copy Directly]
• Spiral matrix III [Walk in a Spiral]
• Fair candy swap [Solve the Equation]
• Monotonic array [Two Pass,One Pass]
• Sort array by parity [Sort, Two Pass, In-place]
• Snakes and ladders [Breadth-First Search]
• Partition array into disjoint intervals [Next Array]
• Maximum sum circular subarray [Kadane, NextArray, PrefixSum+Monoqueue]
• Sort array by parity II [Two Pass, Read/Write Heads]
• 3 sum with multiplicity [Three Pointer, Counting with Cases]
• Three equal parts [Equal Ones]
• Beautiful array [Divide and Conquer]
• Valid mountain array [One Pass]
• Minimum increment to make array unique [Counting, Maintain Duplicate Info]¶
• Most stones removed with same row or column [DFS, Union-Find]
• Largest time for given digits [Brute Force]
• Reveal cards in increasing order [Simulation]
• Largest Component Size By Common Factor [Union-Find]
• Array of doubled pairs [Greedy]
• N-repeated element in size 2N array [Count, Compare]
• Longest turbulent subarray [Sliding Window]
• Sum of even numbers after queries [Maintain Array Sum]
• Add to array form of integer [Schoolbook Addition]
• Find the town judge
• Available captures for rook
• Find common characters
• Minimum domino rotations for equal row
• Pairs of songs with total durations divisible by 60
• Best sightseeing pair
• Binary prefix divisible by 5
• Partition array into 3 parts with equal sum
• Matrix cells in distance order
• Maximum sum of two non overlapping subarrays
• Height checker
• Grumpy bookstore owner
• Flip columns for max number of equal rows
• Number of submatrices that sum to target
• Sum of digits in minimum number
• Duplicate zeros
• Statistics from large sample
• Two sum less than K
• Corporate flight bookings [Line Sweep]
• Decrease elements to make array zigzag
• Invalid transactions [Sliding Window, Line Sweep]
• Diet plan performance [Sliding Window]
• Distance between bus stops
• Minimum absolute difference
• Get equal substrings within budget [Sliding Window]
• Queens that can attack the king
• Cells with odd values in matrix
• Shift 2D grid
• Count servers that communicate
• Find winner on a tic-tac-toe game
• Find numbers with even number of digits
• Replace elements with greatest element on right side
• Find N unique integers sum up to zero
• Decompress run length encoded list
• Distinct echo substrings [KMP, Sliding Window, Rabin-Karp]
• Sort the matrix diagonally [Sort]
• Rank transform of an array
• Filter restaurants by vegan friendly price distance [Sort]
• The K weakest rows [OrderedDict, Quick Select]
• Number of sub-arrays of size K and average >= threshold
• Check if N and its double exist
• Count negative numbers in a sorted matrix
• Bulb switcher III
• Lucky numbers in a matrix
• Create target array in the given order
• Find lucky integer in an array
• Count largest group
• Number of steps to reduce a number in binary representation to one
• Minimum value to get positive step by step sum
• Maximum points you can obtain from card [Sliding Window]
• Counting elements
• Perform string shifts
• Leftmost column with at least a one
• Kids with the greatest number of candies
• Check if all 1’s are at least length k places away