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⏱ 7 min read

📋 Master Problem List

164
Total Problems
56
Solved ✓
108
In Progress ○

Arrays & Sliding Window

#3 Longest Substring Without Repeating Characters ✓ Solved
Medium arrays sliding window strings
🔗 Problem 💻 Solution
#121 Best Time to Buy and Sell Stock ✓ Solved
Easy arrays sliding window
🔗 Problem No notes yet
#424 Longest Repeating Character Replacement ✓ Solved
Medium arrays sliding window strings
🔗 Problem No notes yet
#567 Permutation in String ✓ Solved
Medium arrays sliding window strings
🔗 Problem No notes yet
#76 Minimum Window Substring ✓ Solved
Hard arrays sliding window strings
🔗 Problem No notes yet
#904 Fruit Into Baskets ○ Todo
Medium arrays sliding window
🔗 Problem No notes yet
#560 Subarray Sum Equals K ○ Todo
Medium arrays sliding window hashing
🔗 Problem No notes yet
#930 Binary Subarrays With Sum ○ Todo
Medium arrays sliding window
🔗 Problem No notes yet
#209 Minimum Size Subarray Sum ○ Todo
Medium arrays sliding window
🔗 Problem No notes yet
#992 Subarrays with K Different Integers ○ Todo
Hard arrays sliding window
🔗 Problem No notes yet
#340 Longest Substring with At Most K Distinct Characters ○ Todo
Hard arrays sliding window strings
🔗 Problem No notes yet
#1004 Max Consecutive Ones III ○ Todo
Hard arrays sliding window
🔗 Problem No notes yet
#1248 Count Number of Nice Subarrays ○ Todo
Hard arrays sliding window
🔗 Problem No notes yet
#239 Sliding Window Maximum ○ Todo
Hard queues arrays sliding window
🔗 Problem No notes yet

Two Pointers

#125 Valid Palindrome ✓ Solved
Easy arrays two pointers strings
🔗 Problem No notes yet
#167 Two Sum II - Input Array Is Sorted ✓ Solved
Medium arrays two pointers
🔗 Problem No notes yet
#15 3Sum ✓ Solved
Medium arrays two pointers
🔗 Problem No notes yet
#11 Container With Most Water ✓ Solved
Medium arrays two pointers
🔗 Problem No notes yet
#42 Trapping Rain Water ✓ Solved
Hard arrays two pointers
🔗 Problem No notes yet
#88 Merge Sorted Array ✓ Solved
Easy searching sorting arrays two pointers
🔗 Problem 💻 Solution
#75 Sort Colors ✓ Solved
Medium searching sorting arrays two pointers
🔗 Problem 💻 Solution

Strings

#242 Valid Anagram ✓ Solved
Easy strings
🔗 Problem No notes yet
#49 Group Anagrams ✓ Solved
Medium strings hashing
🔗 Problem No notes yet
#271 Encode and Decode Strings ✓ Solved
Medium strings
🔗 Problem 📋 Approach
#5 Longest Palindromic Substring ✓ Solved
Medium strings two pointers
🔗 Problem No notes yet
#647 Palindromic Substrings ○ Todo
Medium strings two pointers
🔗 Problem No notes yet
#412 Fizz Buzz ✓ Solved
Easy strings
🔗 Problem 💻 Solution
#14 Longest Common Prefix ✓ Solved
Easy strings
🔗 Problem 📋 Approach
#68 Text Justification ✓ Solved
Hard strings
🔗 Problem 📋 Approach

Linked List

#141 Linked List Cycle ✓ Solved
Easy linked list two pointers
🔗 Problem 📋 Approach
#876 Middle of the Linked List ✓ Solved
Easy linked list two pointers
🔗 Problem 📋 Approach
#206 Reverse Linked List ✓ Solved
Easy linked list
🔗 Problem 📋 Approach
#21 Merge Two Sorted Lists ✓ Solved
Easy linked list
🔗 Problem 📋 Approach
#19 Remove Nth Node From End of List ✓ Solved
Medium linked list two pointers
🔗 Problem 📋 Approach
#2 Add Two Numbers ✓ Solved
Medium linked list
🔗 Problem 📋 Approach
#143 Reorder List ✓ Solved
Medium linked list two pointers
🔗 Problem 📋 Approach
#25 Reverse Nodes in K-Group ✓ Solved
Hard linked list
🔗 Problem 📋 Approach
#138 Copy List with Random Pointer ✓ Solved
Medium linked list
🔗 Problem 📋 Approach
#146 LRU Cache ○ Todo
Medium linked list hashing
🔗 Problem No notes yet
#287 Find the Duplicate Number ✓ Solved
Medium linked list
🔗 Problem 📋 Approach

Stacks

#20 Valid Parentheses ○ Todo
Easy stacks
🔗 Problem No notes yet
#155 Min Stack ○ Todo
Medium stacks
🔗 Problem No notes yet
#739 Daily Temperatures ○ Todo
Medium stacks
🔗 Problem No notes yet
#84 Largest Rectangle in Histogram ○ Todo
Hard stacks
🔗 Problem No notes yet

Trees

#104 Maximum Depth of Binary Tree ✓ Solved
Easy tree
🔗 Problem 📋 Approach
#100 Same Tree ✓ Solved
Easy tree
🔗 Problem 📋 Approach
#226 Invert Binary Tree ✓ Solved
Easy tree
🔗 Problem 📋 Approach
#101 Symmetric Tree ✓ Solved
Easy tree
🔗 Problem 📋 Approach
#110 Balanced Binary Tree ✓ Solved
Medium tree
🔗 Problem 📋 Approach
#102 Binary Tree Level Order Traversal ✓ Solved
Medium tree
🔗 Problem 📋 Approach
#103 Binary Tree Zigzag Level Order Traversal ✓ Solved
Medium tree
🔗 Problem 📋 Approach
#98 Validate Binary Search Tree ○ Todo
Medium tree
🔗 Problem No notes yet
#235 Lowest Common Ancestor of BST ○ Todo
Medium tree
🔗 Problem No notes yet
#124 Binary Tree Maximum Path Sum ○ Todo
Hard tree
🔗 Problem No notes yet
#297 Serialize and Deserialize Binary Tree ○ Todo
Hard tree
🔗 Problem No notes yet

Searching & Sorting

#704 Binary Search ✓ Solved
Easy searching sorting binary search
🔗 Problem 💻 Solution
#35 Search Insert Position ✓ Solved
Easy searching sorting binary search
🔗 Problem 📋 Approach
#744 Find Smallest Letter Greater Than Target ✓ Solved
Easy searching sorting
🔗 Problem 📋 Approach
#169 Majority Element ✓ Solved
Easy searching sorting arrays
🔗 Problem 💻 Solution
#34 Find First and Last Position of Element in Sorted Array ✓ Solved
Medium searching sorting
🔗 Problem 💻 Solution
#540 Single Element in a Sorted Array ✓ Solved
Medium searching sorting
🔗 Problem 💻 Solution
#gfg-rotation-count Rotation Count in Rotated Sorted Array ○ Todo
Medium searching sorting
🔗 Problem 📋 Approach 💻 Solution
#153 Find Minimum in Rotated Sorted Array ✓ Solved
Medium searching sorting binary search
🔗 Problem 💻 Solution
#33 Search in Rotated Sorted Array ✓ Solved
Medium searching sorting binary search
🔗 Problem 💻 Solution
#gfg-infinite-sorted Find Position in Infinite Sorted Array ○ Todo
Medium searching sorting
🔗 Problem 📋 Approach
#gfg-first-one-binary Index of First 1 in Infinite Binary Array ○ Todo
Medium searching sorting
🔗 Problem 📋 Approach
#162 Find Peak Element ✓ Solved
Medium searching sorting binary search
🔗 Problem 💻 Solution
#852 Peak Index in a Mountain Array ✓ Solved
Medium searching sorting binary search
🔗 Problem 💻 Solution
#gfg-search-matrix Search in Row-Column Sorted Matrix ✓ Solved
Medium searching sorting arrays
🔗 Problem No notes yet
#74 Search a 2D Matrix ✓ Solved
Medium searching sorting arrays
🔗 Problem No notes yet
#gfg-allocate-pages Allocate Minimum Pages ✓ Solved
Hard searching sorting
🔗 Problem 📋 Approach
#875 Koko Eating Bananas ✓ Solved
Medium searching sorting binary search
🔗 Problem No notes yet
#981 Time Based Key-Value Store ✓ Solved
Medium searching sorting binary search
🔗 Problem No notes yet
#88 Merge Sorted Array ✓ Solved
Easy searching sorting arrays two pointers
🔗 Problem 💻 Solution
#148 Sort List ✓ Solved
Medium searching sorting linked list
🔗 Problem 💻 Solution
#179 Largest Number ✓ Solved
Medium searching sorting arrays
🔗 Problem 💻 Solution
#75 Sort Colors ✓ Solved
Medium searching sorting arrays two pointers
🔗 Problem 💻 Solution
#1095 Find in Mountain Array ✓ Solved
Hard searching sorting binary search
🔗 Problem 💻 Solution
#4 Median of Two Sorted Arrays ✓ Solved
Hard searching sorting binary search
🔗 Problem 📋 Approach 💻 Solution
#410 Split Array Largest Sum ○ Todo
Hard searching sorting binary search
🔗 Problem No notes yet
#23 Merge k Sorted Lists ✓ Solved
Hard searching sorting linked list heaps
🔗 Problem 📋 Approach
#315 Count of Smaller Numbers After Self ○ Todo
Hard searching sorting
🔗 Problem No notes yet
#164 Maximum Gap ○ Todo
Hard searching sorting
🔗 Problem No notes yet
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