Compilare: user.cpp: In function ‘int main()’: user.cpp:37:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < v[j].size(); ++i) ^ user.cpp:21:33: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d %d", &n, &m); ^ user.cpp:26:44: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d %d %d", &x, &y, &c); ^