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AI Features

CIP Part 2 C#

1.Two Pointers

K-diff Pairs in an Array Solution: K-diff Pairs in an Array Longest Mountain in Array Solution: Longest Mountain in Array Meeting Scheduler Solution: Meeting Scheduler Maximize Greatness of an Array Solution: Maximize Greatness of an Array Find the Original Typed String I Solution: Find the Original Typed String I Remove Duplicates from Sorted List II Solution: Remove Duplicates from Sorted List II Count the Number of Fair Pairs Solution: Count the Number of Fair Pairs Sum of Square Numbers Solution: Sum of Square Numbers Find Beautiful Indices in the Given Array II Solution: Find Beautiful Indices in the Given Array II Number of Subsequences That Satisfy the Given Sum Condition Solution: Number of Subsequences That Satisfy the Given Sum Condi Zigzag Iterator Solution: Zigzag Iterator Length of Last Word Solution: Length of Last Word

2.Fast and Slow Pointers

3.Sliding Window

Longest Substring with At Most K Distinct Characters Solution: Longest Substring with At Most K Distinct Characters Maximum Points You Can Obtain from Cards Solution: Maximum Points You Can Obtain from Cards Minimum Swaps to Group All 1's Together II Solution: Minimum Swaps to Group All 1's Together II Maximum Number of Occurrences of a Substring Solution: Maximum Number of Occurrences of a Substring Count Number of Nice Subarrays Solution: Count Number of Nice Subarrays Maximum Erasure Value Solution: Maximum Erasure Value Maximum Sum of Distinct Subarrays With Length K Solution: Maximum Sum of Distinct Subarrays With Length K Longest Nice Subarray Solution: Longest Nice Subarray Count Vowel Substrings of a String Solution: Count Vowel Substrings of a String Reschedule Meetings for Maximum Free Time I Solution: Reschedule Meetings for Maximum Free Time I Grumpy Bookstore Owner Solution: Grumpy Bookstore Owner Longest Strictly Increasing or Strictly Decreasing Subarray Solution: Longest Strictly Increasing or Strictly Decreasing Suba

4.Intervals

5.In-Place Manipulation of a Linked List

6.Heaps

Sort Characters By Frequency Solution: Sort Characters By Frequency Furthest Building You Can Reach Solution: Furthest Building You Can Reach Trapping Rain Water II Solution: Trapping Rain Water II Maximum Number of Events That Can Be Attended Solution: Maximum Number of Events That Can Be Attended Single-Threaded CPU Solution: Single-Threaded CPU Hand of Straights Solution: Hand of Straights Last Stone Weight Solution: Last Stone Weight

7.K-way merge

8.Top K Elements

9.Modified Binary Search

Search a 2D Matrix Solution: Search a 2D Matrix Find the Smallest Divisor Given a Threshold Solution: Find the Smallest Divisor Given a Threshold Zero Array Transformation II Solution: Zero Array Transformation II House Robber IV Solution: House Robber IV Minimum Number of Days to Make m Bouquets Solution: Minimum Number of Days to Make m Bouquets Valid Perfect Square Solution: Valid Perfect Square Peak Index in a Mountain Array Solution: Peak Index in a Mountain Array

10.Subsets

11.Greedy Techniques

Minimum Adjacent Swaps to Make a Valid Array Solution: Minimum Adjacent Swaps to Make a Valid Array Special Binary String Solution: Special Binary String Maximize Distance to Closest Person Solution: Maximize Distance to Closest Person Minimum Number of Taps to Open to Water a Garden Solution: Minimum Number of Taps to Open to Water a Garden Valid Parenthesis String Solution: Valid Parenthesis String Minimum Number of Swaps to Make the String Balanced Solution: Minimum Number of Swaps to Make the String Balanced Minimum Number of Arrows to Burst Balloons Solution: Minimum Number of Arrows to Burst Balloons Minimum Increment to Make Array Unique Solution: Minimum Increment to Make Array Unique Zero Array Transformation III Solution: Zero Array Transformation III

12.Backtracking

Combination Sum II Solution: Combination Sum II

13.Dynamic Programming

Minimum Cost For Tickets Solution: Minimum Cost For Tickets Count Palindromic Subsequences Solution: Count Palindromic Subsequences Unique Paths II Solution: Unique Paths II Best Time to Buy and Sell Stock IV Solution: Best Time to Buy and Sell Stock IV Delete and Earn Solution: Delete and Earn Longest String Chain Solution: Longest String Chain Last Stone Weight II Solution: Last Stone Weight II Stickers to Spell Word Solution: Stickers to Spell Word New 21 Game Solution: New 21 Game Odd Even Jump Solution: Odd Even Jump 2 Keys Keyboard Solution: 2 Keys Keyboard Minimum Cost to Cut a Stick Solution: Minimum Cost to Cut a Stick Domino and Tromino Tiling Solution: Domino and Tromino Tiling Maximum Number of Events That Can Be Attended II Solution: Maximum Number of Events That Can Be Attended II Scramble String Solution: Scramble String Minimum Falling Path Sum Solution: Minimum Falling Path Sum Find the Minimum Amount of Time to Brew Potions Solution: Find the Minimum Amount of Time to Brew Potions Target Sum Solution: Target Sum Maximum Sum Circular Subarray Solution: Maximum Sum Circular Subarray Coin Change II Solution: Coin Change II Maximum Sum of 3 Non-Overlapping Subarrays Solution: Maximum Sum of 3 Non-Overlapping Subarrays Ugly Number II Solution: Ugly Number II Longest Palindromic Subsequence Solution: Longest Palindromic Subsequence Different Ways to Add Parentheses Solution: Different Ways to Add Parentheses Best Time to Buy and Sell Stock with Transaction Fee Solution: Best Time to Buy and Sell Stock with Transaction Fee Minimum Operations to Reduce an Integer to 0 Solution: Minimum Operations to Reduce an Integer to 0

14.Cyclic Sort

15.Topological Sort

16.Sort and Search

Minimum Absolute Difference Solution: Minimum Absolute Difference Most Profit Assigning Work Solution: Most Profit Assigning Work Rank Transform of an Array Solution: Rank Transform of an Array Relative Sort Array Solution: Relative Sort Array

17.Matrices

Search a 2D Matrix II Solution: Search a 2D Matrix II

18.Stacks

Next Greater Element II Solution: Next Greater Element II Sum of Subarray Minimums Solution: Sum of Subarray Minimums Car Fleet Solution: Car Fleet Clear Digits Solution: Clear Digits Remove All Occurrences of a Substring Solution: Remove All Occurrences of a Substring Subarray With Elements Greater Than Varying Threshold Solution: Subarray With Elements Greater Than Varying Threshold 132 Pattern Solution: 132 Pattern Sum of Subarray Ranges Solution: Sum of Subarray Ranges Add Two Numbers II Solution: Add Two Numbers II Reverse Substrings Between Each Pair of Parentheses Solution: Reverse Substrings Between Each Pair of Parentheses Maximum Nesting Depth of the Parentheses Solution: Maximum Nesting Depth of the Parentheses Final Prices With a Special Discount in a Shop Solution: Final Prices With a Special Discount in a Shop Minimum Add to Make Parentheses Valid Solution: Minimum Add to Make Parentheses Valid

19.Graphs

Walls and Gates Solution: Walls and Gates Snakes and Ladders Solution: Snakes and Ladders The Maze Solution: The Maze Shortest Path in Binary Matrix Solution: Shortest Path in Binary Matrix All Nodes Distance K in Binary Tree Solution: All Nodes Distance K in Binary Tree Making A Large Island Solution: Making A Large Island Minimum Edge Reversals So Every Node Is Reachable Solution: Minimum Edge Reversals So Every Node Is Reachable Minimum Knight Moves Solution: Minimum Knight Moves Keys and Rooms Solution: Keys and Rooms Is Graph Bipartite?Solution: Is Graph Bipartite?Possible Bipartition Solution: Possible Bipartition Divide Nodes Into the Maximum Number of Groups Solution: Divide Nodes Into the Maximum Number of Groups Min Cost to Connect All Points Solution: Min Cost to Connect All Points

20.Tree Depth-First Search

Path Sum III Solution: Path Sum III Boundary of Binary Tree Solution: Boundary of Binary Tree Convert Sorted List to Binary Search Tree Solution: Convert Sorted List to Binary Search Tree Sum Root to Leaf Numbers Solution: Sum Root to Leaf Numbers Count Complete Tree Nodes Solution: Count Complete Tree Nodes Nested List Weight Sum Solution: Nested List Weight Sum Binary Tree Postorder Traversal Solution: Binary Tree Postorder Traversal

21.Tree Breadth-First Search

Binary Tree Vertical Order Traversal Solution: Binary Tree Vertical Order Traversal Maximum Width of Binary Tree Solution: Maximum Width of Binary Tree Cousins in Binary Tree Solution: Cousins in Binary Tree Cousins in Binary Tree Solution: Cousins in Binary Tree Minimum Depth of Binary Tree Solution: Minimum Depth of Binary Tree Populating Next Right Pointers in Each Node II Solution: Populating Next Right Pointers in Each Node II Find Largest Value in Each Tree Row Solution: Find Largest Value in Each Tree Row

22.Trie

23.Hash Maps

Make Array Zero by Subtracting Equal Amounts Solution: Make Array Zero by Subtracting Equal Amounts Find Common Characters Solution: Find Common Characters Count Servers that Communicate Solution: Count Servers that Communicate Check If N and Its Double Exist Solution: Check If N and Its Double Exist Check If Array Pairs Are Divisible by k Solution: Check If Array Pairs Are Divisible by k Rabbits in Forest Solution: Rabbits in Forest Max Sum of a Pair With Equal Sum of Digits Solution: Max Sum of a Pair With Equal Sum of Digits Longest Harmonious Subsequence Solution: Longest Harmonious Subsequence Finding 3-Digit Even Numbers Solution: Finding 3-Digit Even Numbers Subarray Sums Divisible by K Solution: Subarray Sums Divisible by K Number of Black Blocks Solution: Number of Black Blocks Minimum Number of Steps to Make Two Strings Anagram Solution: Minimum Number of Steps to Make Two Strings Anagram Degree of an Array Solution: Degree of an Array Make Sum Divisible by P Solution: Make Sum Divisible by P Find the Prefix Common Array of Two Arrays Solution: Find the Prefix Common Array of Two Arrays Find Missing and Repeated Values Solution: Find Missing and Repeated Values Number of Divisible Triplet Sums Solution: Number of Divisible Triplet Sums Number of Matching Subsequences Solution: Number of Matching Subsequences

24.Knowing What to Track

Minimum Operations to Write the Letter Y on a Grid Solution: Minimum Operations to Write the Letter Y on a Grid Unique Length-3 Palindromic Subsequences Solution: Unique Length-3 Palindromic Subsequences Shortest Palindrome Solution: Shortest Palindrome Find the Celebrity Solution: Find the Celebrity Kids With the Greatest Number of Candies Solution: Kids With the Greatest Number of Candies Fruits Into Baskets II Solution: Fruits Into Baskets II Number of Good Pairs Solution: Number of Good Pairs Maximum Product of Three Numbers Solution: Maximum Product of Three Numbers Remove Outermost Parentheses Solution: Remove Outermost Parentheses Max Chunks To Make Sorted Solution: Max Chunks To Make Sorted Count Vowel Strings in Ranges Solution: Count Vowel Strings in Ranges Shortest Subarray with Sum at Least K Solution: Shortest Subarray with Sum at Least K Word Subsets Solution: Word Subsets Find the Highest Altitude Solution: Find the Highest Altitude Summary Ranges Solution: Summary Ranges Special Array I Solution: Special Array I Number of Ways to Split Array Solution: Number of Ways to Split Array String Compression III Solution: String Compression III Find Longest Special Substring That Occurs Thrice I Solution: Find Longest Special Substring That Occurs Thrice I Guess the Word Solution: Guess the Word Best Sightseeing Pair Solution: Best Sightseeing Pair Shortest Unsorted Continuous Subarray Solution: Shortest Unsorted Continuous Subarray Bitwise ORs of Subarrays Solution: Bitwise ORs of Subarrays Check if Array Is Sorted and Rotated Solution: Check if Array Is Sorted and Rotated Valid Word Solution: Valid Word Running Sum of 1d Array Solution: Running Sum of 1d Array Find Numbers with Even Number of Digits Solution: Find Numbers with Even Number of Digits Maximum Difference Between Increasing Elements Solution: Maximum Difference Between Increasing Elements

25.Union Find

Power Grid Maintenance Solution: Power Grid Maintenance Number of Operations to Make Network Connected Solution: Number of Operations to Make Network Connected

26.Custom Data Structures

27.Bitwise Manipulation

Single Number III Solution: Single Number III Power of Four Solution: Power of Four

28.Math and Geometry

The kth Factor of n Solution: The kth Factor of n Find the Winner of the Circular Game Solution: Find the Winner of the Circular Game Build Array from Permutation Solution: Build Array from Permutation Minimum Moves to Equal Array Elements Solution: Minimum Moves to Equal Array Elements Angle Between Hands of a Clock Solution: Angle Between Hands of a Clock Type of Triangle Solution: Type of Triangle Convert Binary Number in a Linked List to Integer Solution: Convert Binary Number in a Linked List to Integer Count the Hidden Sequences Solution: Count the Hidden Sequences Find N Unique Integers Sum up to Zero Solution: Find N Unique Integers Sum up to Zero Excel Sheet Column Number Solution: Excel Sheet Column Number Water Bottles Solution: Water Bottles Excel Sheet Column Title Solution: Excel Sheet Column Title Ugly Number Solution: Ugly Number Reach a Number Solution: Reach a Number

Solution: Find Common Characters

C# solution for the Find Common Characters problem using the Hash Maps pattern.

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Statement

Given an array of strings words, return an array containing every character that appears in each string in words, including duplicates. If a character occurs multiple times in all strings, include it in the result that many times. The returned characters may be in any order.

Constraints:

$1 \leq$ words.length $\leq 100$
$1 \leq$ words[i].length $\leq 100$ ...