View Compilation Error

0_0_37686906_27167.cpp: In function 'void solve()':
0_0_37686906_27167.cpp:56:40: error: 'tarjan' was not declared in this scope
             if(!dfn[i]) ct++,tarjan(i,i);//要特判根节点 u==fa时确定是根节点
                                        ^