View Compilation Error

111721_0_30568.cpp:8: error: `_int64' does not name a type
111721_0_30568.cpp: In function `void dfs2(int, int)':
111721_0_30568.cpp:41: error: `num' undeclared (first use this function)
111721_0_30568.cpp:41: error: (Each undeclared identifier is reported only once for each function it appears in.)
111721_0_30568.cpp: In function `int main()':
111721_0_30568.cpp:90: error: `num' undeclared (first use this function)