Compilare: user.cpp: In function ‘void dijkstra(int)’: user.cpp:41:40: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0 ; i < g[x].size() ; ++i) ^ user.cpp: In function ‘int main()’: user.cpp:80:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0 ; i < a.size() ; ++i) ^ user.cpp:87:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0 ; i < b.size() ; ++i) ^ user.cpp:94:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0 ; i < c.size() ; ++i) ^ user.cpp:57:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("base3.in" , "r" , stdin); ^ user.cpp:58:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("base3.out" , "w" , stdout); ^