Compilare: main.cpp: In function 'int main()': main.cpp:41:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < adj[i].size(); j++) adj[i][j] = A[adj[i][j]]; ~~^~~~~~~~~~~~~~~ main.cpp:26:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("arb3.in", "r", stdin); ^ main.cpp:27:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("arb3.out", "w", stdout); ^