Array

Array Concepts | Array Tricks

Two Pointers:

• Two/Three/Four Sum:
  •  Two Sum *! | Two Sum II – Input array is Sorted ^ |
  • Two Sum III – Data structure design | Two Sum IV – Input is a BST |
  • 3Sum Simp *! | 3Sum Adv *! | 3Sum Closest | 3Sum Smaller |
  • 4Sum | 4Sum II ! | | Count subsets
• Read and Write pointers:
  • Move Zeroes ! |  Move zeros to left | Remove Element |
  • Remove Duplicates from Sorted Array ! | Remove Duplicates from Sorted Array II
• Other:
  • Squares of a Sorted Array | Subarray Product Less Than K |
  • Backspace String Compare |  Shortest Unsorted Continuous Subarray

Subarray & Subsequences in Array:

• Subarray vs Subsequence for Arrays | Sum of all Subarrays for Arrays |
• Sum of all subsequences for Arrays | Maximum Subarray Sum * |
• Maximum Size Subarray Sum Equals k | Minimum Size Subarray Sum |
• Contiguous Array | Longest subarray with all elements same |

Sliding Window:

• Sliding window Template | Maximum Sum Subarray of Size K |
• Smallest Subarray With a Greater Sum | Birthday Chocolate | Fruit Into Baskets
• Max Consecutive Ones III

Prefix Sum + Suffix Sum: leetcode slugs | g4g | g4gvc

• Product of Array Except Self *! | Subarray Sum Equals K |
• Random Pick with Weight | Sum Of Infinite Array | Continuous Subarray Sum
• XOR Query | Count all sub-arrays having sum divisible by k

Cyclic Sort:

• Cyclic Sort | Missing Number *! | Find all Missing Numbers |
• Find the Duplicate Number * | Find All Duplicates in an Array | Find the Corrupt Pair |
• First Missing Positive ! | Find All Numbers Disappeared in an Array

Intervals / Meeting Rooms:

• Merge Intervals * | Insert Interval * | Interval List Intersections |
• Non-overlapping Intervals * | Meeting Rooms * |
• Maximum Intervals Overlap

Ranges: Summary Ranges | Missing Ranges !

Majority Element: Majority Element ! | Majority Element II

Common numbers in Sorted Array:

• Find smallest common number | Find common elements in three sorted arrays

Shortest Word Distance:

• Shortest Word Distance | Shortest Word Distance II | Shortest Word Distance III

Max Consecutive Ones:

• Max Consecutive Ones | Max Consecutive Ones II |

Peaks and Valley:  Best Time to Buy and Sell Stock ^! | Best Time to Buy and Sell Stock II !

Merge: Merge Sorted Array ! Shuffle: Shuffle an Array ! 

Rotate Array:  Rotate Array | Rotate Array II

Integers as Array:

• Plus One ^  | Add Binary | Multiply Strings ^ | Multiply two arbitrary-precision integers

Misc:

• Running Sum of 1d Array | Find Pivot Index
• Largest Number At Least Twice of Others | Queue Reconstruction by Height
• Array Partition I | Magic Index | Smallest Difference | Next Permutation

Difficult Medium/Hard:

• Trapping Rain Water ^! | Container With Most Water *!
• Sliding Window Maximum ^! | Longest Consecutive Sequence *!
• Count and Say ! | Increasing Triplet Subsequence ! | Task Scheduler ^
• Median of Two Sorted Arrays  ! | Median of Two Sorted Arrays II !
• Find the Celebrity ! | The Skyline Problem ! | First Missing Positive !
• Gas Station ! | Largest Rectangle in Histogram ! | Max Points on a Line !
• Longest Continuous Subarray With Absolute Diff Less Than or Equal to Limit
• Find Numbers with Even Number of Digits