Recall Dojos

About Recall Dojos

Recall Dojos for recognizing and applying individual algorithm patterns under time pressure. Every published session is free to practice without an account. Pro saves your results.

Recall Dojos for deliberate pattern practice

• Vim Dojo — Escape mazes with Vim motions
• Queens Court — Place queens, hit dead ends, backtrack
• Melody Machine — Unlock notes in dependency order
• Bisect — Halve the haystack until it sings
• Pincer — Squeeze the answer from both ends
• Window Shopper — Grow and shrink the perfect window
• Flood Gate — Ripple outward level by level
• Top of the Heap — Sift, pop, and keep the best on top
• Coin Forge — Build big answers from small ones
• Bridge Builder — Merge islands, spot the cycles
• Skyline Stack — Pop the short, push the tall
• Meeting Mania — Book the meeting that ends first
• Signal Runner — Settle the closest node first
• Canopy Walk — Walk the tree in the order it demands
• Merge Yard — Two sorted runs, one belt, never a wrong take
• Bracket Bay — Push, match, and call the break
• Chain Gang — Rewire the pointers without losing the tail
• Bucket Brigade — Hash once, walk the chain, never scan
• Range Sentinel — Answer range queries in log time
• Prefix Grove — One letter, one edge, one node
• Letter Press — Stamp the runs, mirror the ends
• Ledger Line — One running total answers every range
• Ballot Box — One counter finds the majority
• Spiral Patrol — Turn exactly where the law says turn
• Bit Smith — Clear the lowest bit, cancel the noise
• Digit Mill — Peel, carry, and rebuild the number
• Front Desk — Lowest free slot, never lose a guest
• Loom Works — Weave each square from the three behind it
• Span Hall — Raise every short arch before the wide one
• Mask Vault — Every subset is one integer
• Fault Line — Find the tunnel that is the only way in
• Turnstile — Remember only what the rule still needs
• Threshold Gate — Halve the answer, not the array
• Pivot Yard — Place one wagon, discard half the yard
• Horizon Sweep — Only the boundaries ever matter
• Glide Path — Keep only the ones that can still win
• Halfway House — Two halves you can afford, joined by a search
• Return Post — Call into every child, then resolve the node from what came back
• Tier Queue — Snapshot the queue, drain a level, close the row
• Three Colours — White descends, a stamped node is read from the vault, gray is still open
• Tally Rack — Count once, then spend or pour the rack
• Verge Finder — Flip, file the lit card, drop the half the lamp rules out
• Fork Finder — Fold the tree in postorder until two hits meet
• Odometer Roll — Fixed wheels, one menu each — emit at the end, carry when spent
• Splice Bench — Unlink it, hold it, link it back in — one pointer beat per key
• Mirror Swap — Swap the ends, close in, seal — reversal with no second array
• Fuse Line — Sort by start, then extend or emit — one key per bar
• Balance Beam — Two heaps, one boundary: the median and the next rank always at the roots
• Cut Table — Every cut that fits, priced by hand, and the best one sealed
• Reverse Polish — Push operands, pop two into their slots, push one result back
• Stair Descent — One compare retires a whole row or column
• Shorter Wall — Only the shorter wall moves — stamp the container or let the rain in
• Letter Trail — Mark, recurse four ways, restore — until the grid spells the word
• Delve Deep — Push on the way down, read the buffer at a target, pop on the way up
• Choice Ledger — One start-index walk, three record rules
• Root Nursery — Grow a tree back from its sequence, one hole at a time
• Valley Floor — Pop the taller, settle the rectangle
• Ripple Row — Bubble, insertion and selection, one comparison at a time
• Sack Sweep — One capacity row, swept the right way round for each item