用一条线连起所有的圆只能用横线和竖线不能重复

为了方便理解 将圆圈编号：A1←A2←A3←A4←A5（←从这开始）↓````````````````B1←B2←B3←B4↓````````````````↑C1→C2→C3→C4→C5```````````````````↑`````↓D1→D2→D3→D4``D5↑`````````...