Compilare: main.cpp: In function 'int main()': main.cpp:64:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < G[node.x].size(); ++j) ~~^~~~~~~~~~~~~~~~~~ main.cpp:26:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("bellmanford.in", "r", stdin); ^ main.cpp:27:41: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("bellmanford.out", "w", stdout); ^