Expand Around Center Pattern Visualizers

The Expand Around Center pattern is a recurring algorithmic shape that appears across coding interviews and competitive problems. Use it when the problem geometry matches its trigger conditions — recognizing the pattern collapses what looks like a hard problem into a familiar template. These visualizers trace Expand Around Center step-by-step on classics such as Longest Palindromic Substring, Palindromic Substrings, so you can internalize the moves before you ever need them under pressure.