Why Learn Patterns Instead of Problems?
There are thousands of LeetCode problems, but only a few dozen underlying patterns. Interviewers reuse them constantly: sliding window, two pointers, fast & slow pointers, prefix sums, monotonic stacks. Once you can recognize which pattern a problem belongs to, you already know the shape of the solution — the rest is careful implementation.
These visualizers teach recognition. Instead of memorizing solutions, you watch the pointers move, see the state update, and connect every visual step to the exact line of code that causes it.