Compilare: user.cpp: In function ‘int main()’: user.cpp:129:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0; i<V.size(); i++) ^ user.cpp:106:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("spider.in", "r", stdin); ^ user.cpp:107:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("spider.out", "w", stdout); ^ user.cpp:108:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &N, &M); ^ user.cpp:113:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &H[i][j]); ^