Finding the LCS length was one thing. But what if the question asks for ALL possible longest subsequences? That's where backtracking enters the picture.

I thought I had DP figured out. I'd solved house robber with that sweet max(rob_this_house + dp[i-2], skip_this_house) logic. I'd reversed linked lists by imagining "the rest is already solved." But when I faced Longest Common Subsequence, all my mental models fell apart.

No decision tree. No "imagine the rest" logic. No clever way to use previous answers. Just... confusion.

Here's how I finally cracked it.

A conversation about solving the Lowest Common Ancestor problem that reveals one of the most elegant patterns in tree recursion—using return values to communicate information upward through the call stack.

A conversation about solving the Minimum Coin Combination problem that reveals why greedy algorithms sometimes fail—and how recognizing overlapping subproblems is the foundation of dynamic programming thinking.

A conversation about solving the LRU Cache problem that reveals one of the most elegant hybrid data structure designs—and why sometimes the "crazy" idea of combining two data structures is actually brilliant.

A conversation about solving the Widest Binary Tree Level problem that reveals how mathematical position formulas and DFS traversal create an elegant solution—and why we need to track both min and max positions at each level.

Ever seen List<Set<Integer>> rowSets = new ArrayList<>() and wondered "Why not new List<Set<Integer>>()?" This fundamental question about interfaces vs concrete classes trips up many Java learners. Let's clear it up through a real conversation.

A conversation about solving the Subarray Sum Equals K problem that reveals how cumulative sums and hashmaps create an elegant O(n) solution—and why we need that mysterious map.put(0, 1) initialization.

I implemented keyboard navigation for my table, and it worked perfectly—until I tried using the mouse. The selected row would stay gray instead of blue, but only when my mouse was hovering over it. A debugging journey through CSS pseudo-class conflicts.

I just made a commit, so why does VS Code still show that asterisk (*) on my branch name? A debugging journey through Git's "deleted" file status and what to do about it.