All challenges

Find a palindrome walk that visits every open maze cell and ends at the exit.

Draw an axis-aligned polygon that catches more mackerels than sardines.

Recover a hidden sequence of addition and multiplication operators.

Choose edges forming an MST for the source online-spanning-tree instance.

Shift rows and columns to remove demons while preserving fortune pieces.

Construct a Number Loop puzzle with as few valid loop solutions as possible.

Identify the hidden target from a noisy membership-search instance.

Optimize a C++ N-body simulation while preserving numerical correctness.

Optimize a C++ N-body simulation while preserving numerical correctness.

Output a fixed-length graph walk visiting every clearing while delaying valuable first visits.

Track a hidden mole on a rooted tree through subtree queries that can move the target.

Recover a hidden unordered_set bucket count through the original collision-query protocol.