All challenges

Explore a uniform directed cave by marking passages until the treasure appears.

Construct a high-value increasing sequence with strictly increasing adjacent gcds.

Choose powered stations, cables, and radio strengths to cover residents at low cost.

Sort a permutation on a tree using parallel matching swaps with as few rounds as possible.

Choose a vertex service order on a tree whose removals flip unserviced neighbors.

Find the unique centroid of a hidden tree through distance queries.

Find the two anomaly nodes in each tree source case.

Choose item counts for a two-constraint packing instance and maximize total treasure value.

Navigate hidden neighbor orders to visit every graph vertex efficiently.

Rotate railway tiles to form two large loop lines.

Reconstruct a toroidal character matrix that contains many observed strings.

Find a high-value path on a tiled 50 by 50 board without revisiting a tile.