给你n根木棒，请问使用这些木棒，是否有可能让它们头尾相连组成一个正方形？所有的木棒都必须使用。深度优先搜索的正方形问题-N root stick to you, will use the stick, is it possible so that they linked to the formation of a square head? All must use the stick. Depth-first search of the square problem