Compilare: user.cpp: In function ‘int main()’: user.cpp:14:30: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fi,"%d%d", &n, &k); ^ user.cpp:17:38: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fi,"%d%d", &lin, &col); ^ user.cpp:33:38: warning: ‘a’ may be used uninitialized in this function [-Wmaybe-uninitialized] G[a][b].push_back({lin, col}); ^