View Compilation Error

0_0_6865813_19184.cpp: In function `void bfs(int, int, int, int)':
0_0_6865813_19184.cpp:17: error: `low' undeclared (first use this function)
0_0_6865813_19184.cpp:17: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_6865813_19184.cpp:17: error: `up' undeclared (first use this function)
0_0_6865813_19184.cpp:19: error: 'class std::queue<int, std::deque<int, std::allocator<int> > >' has no member named 'top'