There's a road trip game where you look at the three letters on a license plate and try to think of a word that contains all three letters in that order, but not necessarily adjacent. You see "BRN" and someone shouts "BURNING." You see "PLT" and there's "PLATFORM." It's a good game because the difficulty varies wildly. Some letter combos have dozens of common answers. Others seem impossible until someone finds the one obscure word that works.
I built this to settle arguments. You type three letters and it instantly shows you the shortest words that contain those letters as a subsequence.
The matching algorithm
The app loads a word list from a text file on startup. When you enter three letters, it runs every word through a subsequence check. The algorithm walks through the word character by character, looking for each of the three target letters in order. It maintains a position pointer that advances through the word. For each target letter, it searches forward from the current position. If it finds all three before running out of word, it's a match. If any letter is missing or appears out of order, the word is rejected.
This is an O(n) scan per word, where n is the word length, and it runs across the entire dictionary on every keystroke. With a typical English word list in the range of 100,000-200,000 words, the filtering completes in a few milliseconds on any modern browser. No indexing or precomputation needed.
Result ordering
The results are sorted by word length, shortest first, and capped at ten. This was a deliberate choice. In the actual road trip game, shorter words are more impressive answers because the letters are packed tighter. Nobody is impressed when you find a 14-letter word; the letters are bound to show up somewhere in something that long. Finding a 4-letter word that contains "XPL" is the kind of answer that wins the round.
Implementation
The input field auto-capitalizes and strips non-alphabetic characters. A hint below the field shows how many more letters you need to enter. Once you hit three letters, results appear instantly below a divider line. The whole UI fits in a white card on a gray background. It's responsive down to about 480px, which is the size that matters since you're usually playing this on a phone in the passenger seat.
The project is two files: one HTML page and one word list. Everything runs client-side.