dag.cpp: In function 'void read()': dag.cpp:27: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result dag.cpp:28: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result dag.cpp:31: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result dag.cpp: In function 'int search_minimum()': dag.cpp:41: warning: 'node' may be used uninitialized in this function dag.cpp: In function 'void solve()': dag.cpp:41: warning: 'node' may be used uninitialized in this function dag.cpp:41: note: 'node' was declared here