十字链表写的tarjan算法 且缩环成点判断出度-Cross-linked and reduced write tarjan algorithm out-degree loop into a point to judge

求无向图最少加多少条边才能变成双联通图，输入顶点数和变数，然后读入图，利用无向图的Tarjan算法。-At least they try to figure how much to become a double edge Unicom plans, and variable input vertices, and then read into the figure, the use of undirected Tarjan algorithm.

Tarjan的脱机最小公共祖先问题，里面使用了pair,map以及结构体等相关结构-Tarjan off-line least common ancestors problem