OJ Board

I run pass with all the test cases I can find in the forum, but get WA after submiting, please help, thanks.
#include <iostream>
#include <list>
using namespace std;
#ifndef ONLINE_JUDGE
#include <fstream>
ifstream _xin("a.txt");
#define cin _xin
#endif
#define MAX_DEC 30

void print_path(list<int ...