Compilare: user.cpp: In function ‘int main()’: user.cpp:32:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < v[i].size(); j++) ^ user.cpp:15:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("cuplaje.in", "r", stdin); ^ user.cpp:16:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("cuplaje.out", "w", stdout); ^ user.cpp:19:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &N, &M); ^ user.cpp:21:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &b[i]); ^ user.cpp:25:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &x); ^