pitici1.cpp: In function 'void TopologicalSort()': pitici1.cpp:24: warning: comparison between signed and unsigned integer expressions pitici1.cpp: In function 'void Solve()': pitici1.cpp:80: warning: comparison between signed and unsigned integer expressions pitici1.cpp: In function 'int main()': pitici1.cpp:103: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result pitici1.cpp:104: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result pitici1.cpp:106: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result pitici1.cpp:108: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result