Compilare: user.cpp: In function ‘int main()’: user.cpp:78:45: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] else if(v.size()!=0) for(int i=0; i<v.size(); i++) ^ user.cpp:46:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("intrus.in", "r", stdin); ^ user.cpp:47:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("intrus.out", "w", stdout); ^ user.cpp:51:38: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d", &q, &n, &m, &l); ^ user.cpp:56:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &a[i][j]); ^