Cartesian Tree Forum Problem Tutorials # ๐ฏ๐ต (ใใใกใใ) Cartesian Tree ใฎๅฎ่ฃ ใ stack ใ็จใใ O(N) ๆ้ๆง็ฏ - ใใใกใใใฎ็ซถใใญ็ฒพ้ฒ่จ้ฒ