说明：  深度优先搜索算法Matlab源码 ％ 此程序从国外网站收集得到，是标准的深度优先搜索算法，可实现节点遍历和检测回路的功能，详细情况请看原英文注释 ％ 我在此程序中添加了随机性，即遇到分叉时，随机选下一个节点，成为随机深度优先搜索算法
(Depth-first search algorithm Matlab source this procedure site collected from abroad, is the standard depth-first search algorithm, can be achieved and the detection circuit node traversal functions, details see the original English Notes I added this procedure randomness, that is, bifurcation encountered when a randomly selected node, become a random depth-first search algorithm)