Stalagtites and Stalagmites
Place numbers from 1-N in the grid so that each digit appears exactly once in each row and each column. The hints around the grid denote all the increasing or decreasing sequences longer than 2 in the given row/column in the correct order. The sequence is increasing from the tip of the sign.
(Rules and example (N=4) from WPC 2018 IB)
History of the puzzle
Appeared on WPC 2018/Round 12, an "innovatives" round. The puzzles were written by Jiří Hrdina (Czech Rep.). "Stalagtites" are rarely-used form of the word "stalactites".