Prep Notebook

LeetCode tracker

LeetCode problems

289 problems solved on LeetCode, mostly in Java. Below are the ones I've tracked since starting this journal, each with a one-line insight, so this page doubles as my revision sheet.

My LeetCode profile ↗

Solved on LeetCode

289 / 4096

  • Easy 16 / 974
  • Medium 229 / 2136
  • Hard 44 / 986

From my public LeetCode profile, updated 2026-10-31.

Top topics

  • Array 177
  • Dynamic Programming 72
  • String 57
  • Hash Table 56
  • Depth-First Search 52
  • Breadth-First Search 52
  • Matrix 37
  • Sorting 37
  • Binary Search 32
  • Tree 31
  • Binary Tree 30
  • Greedy 28

Tracked problems 20 · 20 solved without help

ProblemPatternLevelStatusKey insightDate
Making A Large Island Graphs Hard Solved Oct 31
Shortest Path in a Grid with Obstacles Elimination Graphs Hard Solved Oct 31
Map of Highest Peak Graphs Medium Solved Multi-source BFS from all water cells; height = BFS distance. Oct 30
Surrounded Regions Graphs Medium Solved DFS/BFS from border O's to mark safe cells; flip every unmarked O to X. Oct 30
Snakes and Ladders Graphs Medium Solved BFS over squares, up to 6 edges each; map square number to boustrophedon row/col. Oct 30
Minimum Genetic Mutation Graphs Medium Solved BFS over gene strings: each valid one-letter change in the bank is an edge. Oct 29
Keys and Rooms Graphs Medium Solved Reachability from room 0 with DFS/BFS; check every room got visited. Oct 29
Shortest Bridge Graphs Medium Solved DFS to mark the first island, then multi-source BFS from it until you reach the second. Oct 29
Shortest Path in Binary Matrix Graphs Medium Solved Oct 29
Pacific Atlantic Water Flow Graphs Medium Solved Oct 28
Number of Closed Islands Graphs Medium Solved Oct 28
Find if Path Exists in Graph Graphs Easy Solved Oct 24
Max Area of Island Graphs Medium Solved Oct 24
01 Matrix Graphs Medium Solved Oct 24
Number of Provinces Graphs Medium Solved Oct 24
Redundant Connection Graphs Medium Solved Oct 24
Bulls and Cowsmy code Hashing Medium Solved Oct 11
Rank Teams by Votesmy code Sorting Medium Solved Oct 11
Find K Closest Elements Heap Medium Solved Oct 10
Online Election Binary Search Medium Solved Oct 10